Please help - what is going on :'(

[Searchersoul17]

Around 9 weeks ago I had an STD scare from receiving oral sex from a CSW. This encounter led me to deal with a lot of stress & panic of the thought of catching something. Although I had no physical symptoms I was worried that I might've contracted something like Herpes. My diet was very poor at this time & I slept a lot. My metabolism seemed completely screwed as I hardly had the urge to pass stools anymore, I only passed stools once in the morning as opposed to my usual bowel habits. I was dealing with some episodes of diarrhoea & constipation, rectal leakage along with bloating & gas. So I had all the STD tests done at 4 weeks and they all came back negative except HSV-1 which I had since I was young.

I felt reassured after receiving the results and this decreased my stress levels - I was back in the gym & eating and drinking well. However the symptoms still persist; slow metabolism, legs sometimes feel weak when I walk, parasthesia throughout the day (tingling, palpitations and numbnesson my legs/arms), and just recently I've found out that I have Dermatographia (welts like hives when I scratch, they appear like lines).

So after some research I've found out that an under-active thyroid (hypothyroidism) can cause slow metabolism, Dermatographia in some cases, fatigue & muscle weakness. I just don't know which direction to look towards, I feel like I may have an auto-immune disorder, something that's affecting my nerves or gut, or problems with my immune system. I am 19 (male) in general really active and healthy so I don't know what the trigger was. Please help if you can :(