Could candida be causing all these symptoms, and is it dangerous?

Back in December i had some dental work done, (root canal/tooth colored fillings), and then about 2 weeks later i found out i was pregnant. Sadly, about 2 weeks after finding out i was pregnant, i miscarried. During this time, every now and then i would get brain fog, and mild headaches that would come and go. After the miscarriage, I didn't have any brain fog for about 2 weeks. One day, the brain fog came back, and has been constant for almost a month now. I would like to list other symptoms i have:

Headaches-Sometimes both sides by the temples, sometimes just one side, and pretty bad
24/7 brain fog for a month as mentioned
Phlem in throat which i believe is post nasal drip
Itching in ears, not often, but sometimes
Feeling of pressure in the back of the head
Neck is super sore/also sore shoulders, sometimes i feel shooting pains in them
Pressure made much worse when i lean my head down
Sensitivity to light/sound (This is pretty bothersome, as any bright lights really bother my eyes, and sounds are enhanced
Symptoms often made worse by light/computer/tv
Fatigue/tired eye feeling/achy joints
Lower back pain/sore hips (not sure if linked to head symptoms)
Eye floaters/clouded vision sometimes
Cold hands/feet sometimes
Dizziness with any quick movement (When standing up/in the car/made worse by hot baths)

Other info: I was suffering from constipation/bloating a while before all these symptoms started, and went to my gastro doctor who did some testing. He said my stool came back with more yeast than normal, so he prescribed me nystatin for oral candida, and wanted to do a colonoscopy just to be safe, which had to be put off as i was advised not to go under any kind of anesthesia/sedatives with my head symptoms

So when i first experienced this i went to an urgent care clinic as getting into doctors was a long wait. He prescribed me antibiotics for tension headaches, which got rid of the headaches for a few hours, but the brain fog etc still remained. A week or so later, my brain fog seemed really really bad, and my headaches really hurt. I went to the ER because i couldn't stop crying, not knowing what is happening to me, and why my mental state is so impaired all of a sudden. The guy who saw me at the ER said it is hard to diagnose brain fog as there could be many causes, so he prescribed me medrol dose pack, and said if that doesn't help to follow up with my GP whose appointment i had the following Tuesday. He looked in my ears/throat and said all looked okay. I took the meds, and they did nothing.

So i go to a GP as my husband and i recently got health insurance, and she looked in my ears, and throat, and said i had a sinus infection. Her words were "No wonder you have been feeling so poorly, it is making my head hurt just looking at it." She prescribed me Ceftin, and a Nasal spray. First day i took the antibiotics, it intensified all my symptoms MAJORLY. I thought i would persevere seems maybe the intensified feeing was due to bacteria being killed off. After 3 days, i felt no better, and gave my GP a call. She said to me that the meds weren't strong enough, and i need to go to an emergency clinic to get antibiotics by IV, to kill the infection. She also said my blood work came back normal. She tested thyroid, motor neuron disease, and my blood count.

So i go to the clinic with my mom, and i explain the situation to the doctor, who then looks really concerned, turns to my mom, and says "You need to take your daughter to the ER immediately to rule out meningitis, and demand a CT scan. So we got to the ER, and i tell them someone demanded i have a CT scan to rule out meningitis( i am a bit confused with this, because if i am not mistaken, i thought meningitis was diagnosed with a spinal tap, not by a CT scan). They give me a mask to wear in the waiting room, which was super embarrassing. So i get called back to the room, and the nurse takes all my symptoms. Says that it is definitely not meningitis just by looking at me, because i would not be how i am after having meningitis for weeks. She looks in my ears, and say all looks good (Contradiction to my GP who said they had fluid in and looked bad), but she did say i have some postnasal drip. They do blood tests, and send me for a CT scan without contrast. CT scan comes back normal, as does blood work. They say they tested my Complete blood count, which came back fine, and if there was some kind of infection, my white blood cell numbers would be raised. So after 7 hours at the ER, and a major scare of wondering if meningitis was the cause, I was prescribed yet another round of antibiotics for a sinus infection, as they said clearly the old antibiotics were not working, and told me to follow up with an ENT doctor. I take the first one today, and once again, my brain fog is AWFUL. I am going to try and finish the 10 day course, but i don't hold out much hope. The doctor said any kind of infection would show up on a blood test as the body is trying to fight it, and the levels raise, so not sure why they are prescribing me meds for sinuses again.

I am so frustrated! I do not know what to do next. I am glad obviously that the CT scan came back clear, but i am no closer to a diagnosis, and this is ruining my life. Doctors see normal blood, and seem to think if that is normal there is nothing wrong, and i am at my wits end. I am wasting more and more money visiting doctors, and no one seems to know what is wrong, and every doctor is telling me something different. I would like to add that i do not think this is related to depression/anxiety in any way. I do not have any history of this, and I have a wonderful husband, and we have a great life together. Obviously we were both upset about the miscarriage, but we were strong together, and were dealing with it. I have cried often though since the constant brain fog occurred. I just worry i may never feel the same way ever again, and i do not know the cause. I do worry that something is really wrong with my health, but only because this does not seem to be going away.

What should my next step be? I have read of other things that can cause my symptoms, but not sure how to get tested for them, or what specialist to consider next. I feel like the doctors i have seen have not been thorough enough at all. I mean, would they not do all tests to rule out anything really serious? Any advice? I want my life back