New doctor--need advice

I went to see a new doctor last week and he told me what he thinks is going on with me. Bear in mind, he is an MD but "alternative;" so his views are not what other docs would have.

My main complaints to him were fatigue, brain fog, amenorrhea, inability to lose weight despite diet and exercise, weight gain (for me just 6 pounds, but when you are 5'4" and have been the same weight since 8th grade, its a lot). I also mentioned anxiety, mild depression, difficulty concentrating, and times of constipation alternating with diarrhea.

He suspects:
-hypothyroidism, even though two different docs have tested TSH and it was "normal"
-possible adrenal fatigue
-estrogen dominance
-possible candida overgrowth, which has led to leaky guy syndrome, which has led to malnourishment/fatigue/hormone imbalances

Does anyone know about the candida thing? I did an at-home saliva test and it was negative for candida. I only seem to have the general body symptoms; I have not had a yeast infection in 6 years. How else can they test for it? He is recommending all kinds of tests, $3400 worth, and I just don't think I need all of them.

Do any regular docs do saliva cortisol tests? What about female hormones? I really think that, and/or hypothyroidism is my problem.

Also, my symptoms have been 90% better since last week. What is going on here? I felt great immediately post-Mirena removal, that lasted for 2-3 weeks, then I got hit again and felt rotten for 3-5 days, then better again.

Help!?!?! Any advice appreciated.