What cortisol test was done and what was the result and reference range?
If you want information to give your doctor, in order to get the needed tests, I suggest this link. Have a look at least through the first two pages, and more if you want to see the discussion and scientific evidence supporting the suggestions on page 2. Clinical treatment outlined in the paper is different than the practices of most doctors, but it is hard to dispute the supporting evidence.
http://www.thyroiduk.org.uk/tuk/TUK_PDFs/diagnosis_and_treatment_of_hypothyroidism_issue_1.pdf
So my results came back normal.
My TSH was 3.79 mU/L with a Range of 0.27-4.2
Apparently because this was within range they didn't bother testing my sample for Free T4 and Free T3.
Your symptoms sound more like hyperthyroidism than hypo, especially the rapid heart rate, shortness of breath and mood swings. Some of the others sound like blood sugar swings... When are you testing your blood sugar levels? In order to get meaningful readings, you need to check them fasting, 1 and 2 hours post prandial (after eating).
Have you had any thyroid function tests? You should ask your doctor to test Free T3 and Free T4, which are actual thyroid hormones, along with TSH which is the pituitary hormone that stimulates the thyroid to produce the thyroid hormones. Many doctors will try to test only TSH and say that's enough, but that's not correct. You need all three tests, because TSH does not tell the whole story.
Also, since you have such fatigue, you should ask to get test for vitamin B-12. B-12 deficiency can cause horrible fatigue, brain fog (spaced out feeling), inability to concentrate, etc.
Please note that anxiety and/or depression can cause these same symptoms.