What Causes Lighheadedness, Diarrhea And Loss Of Appetite?

Question : Three weeks ago I started feeling light headed and shaky that progressed into loose stools and no appetite, constant feeling of nausea difficulty sleeping and sweaty feet. I was in a store and felt like I was going to pass out, heart started racing and I was hyperventaling. Went to ER and the done a CBC and said I had dehydration and urine sample showed UTI and my BP and Pulse was elevated. Started Cipro took it for 4 days and started to feel slowly better with better appetite, but still shaky. During the week I was feeling better I got 20 tick bites. Went to primary care doc and he said I just have anxiety, cause he done a thyroid test that was normal T4 10.5--ug/dL T3 Uptake--30.1% Free Thyroxine Index--3.2 TSH-- 1.045. I now have no appetite what so ever and have barely eaten anything, dry mouth, mild stomach pains. I wake up shaking and am shaky. Went to ER last night done EKG due to palpitations I have been having and was told anxiety. They said the tick bites look ok, but my temp was 99.3. They only checked my pee and said I had ketones in it since I haven't been eating. What could be the problem? I thought I was hyperthyroidism. I am scared that I have some sort of infection or disease.

I only flush when I get nervous. I get mild heeadaches. My feet sweat and are usually cold. Just stopped birth control pill last week of July had withdraw bleeding and I just got my first period after BC about 4-5 days ago. No smoking.