Can someone please help. At my wits end

Hi all,

I wrote on here a while back about some very strange symptoms that came on when i found out i was pregnant. Light sensitivity, and a drunk/high feeling that would come and go. I then miscarried, and for 3 weeks felt fine. Then one day, i woke up with the drunk feeling constantly, and the light sensitivity, and have been this way for 5 months straight, with no break in symptoms. I saw a gastro in February who found yeast overgrowth in my stool. I thought nothing of it, i didn't even know what it was, until i started researching. He gave me nystatin, and my symptoms never changed. Started researching yeast, and was certain it was causing my issues. I went on a strict diet, and found a doctor who deals with these types of issues seems i read a lot about regular doctors who don't believe in it. She put me on nystatin/diflucan for a month, and i had no relief in symptoms. Things i have tested for:

Thyroid-Fine
Diabetes-Negative
General blood testing- Ok (But few neutrophils that fight bacteria 2 points out of range), overall white blood count within range
CT head scan-Normal
food allergy testing shows no allergies
Probiotics tried (None make any difference)
Doctor has tried (Metronidazole as it can help fight certain bacteria in the body)- Makes symptoms 10x worse
Nystatin and diflucan make symptoms feel 10x worse
GP a while ago said i had a sinus infection (I don't think she knew what was wrong really, she just went off me saying i had some post nasal drip and my nose runs a bit), so she gave me ceftin- This also made my symptoms feel 10x worse.

So i am not sure if any Antibiotic is making me feel worse, or these certain ones irritate whatever i have going on. So i just did the CDSA stool analysis that i heard really helps show up yeast, and what is resistant/sensitive to it. I just got the results, and it shows no yeast present in my stool, and this test took 3 different samples from different days. Now i am completely disheartened because i have no idea why i feel this way, and it is really scaring me. Does anyone know other things that can cause these issues? I will give a quick run down of symptoms.

Constant drunk/high feeling
Light sensitivity (Not so bad outside in natural light, much worse with indoor lighting) It feels like when you first wake up and turn a lamp on, but my eyes never adjust to the light.
Undigested food in stools
Hard pellet stools
Carbs/Sugar/Caffeine make symptoms worse
Random itching over skin but with no rash (Sometimes mild hives are present)
Heavy feeling eyes/Sometimes feel very sleepy after food
Feel at best first thing in the morning
Sneezing sometimes/runny nose
Post nasal drip sometimes
Itchy anus/inside ears/nose
Slight runny nose sometimes
Had chronic constipation before this for 2 months
Had root canal-Had tooth removed, made no difference

I am at my wits end, and i worry i have something really rare and life threatening.