So i havent been feeling normal lately...?

So the other day, i was at my friends house watching a movie, then i got really antsy and didnt want to be there at all. so i ended up leaving and going out, and started feeling really weird. Almost like really flustered and confused, but then it went away in like a minute. The next day i went to the beach with my friend, i was surfing for about a hour and a half. We then left, and we went to get some food. I got started to get really cold, and couldnt stop shaking even though my friend said it was hot in the building. We assumed i was dehydrated, so i drank about 3 cups of water and we headed home. For about 10 to 15 more minutes i was still real shakey and felt really weird, almost like what a panic attack would feel like id assume. (my heart felt really flustered kind of) it then went away and i felt normal, but about 2 hours later i started feeling really flustered again and i had really bad cotton mouth. i went to the minute clinic, and the nurse told me everything was fine except my pulse was slightly up, and that might be from dehydration, so she told me to go to the hospital. There they did blood work, all my vitals were fine, and my hearts electrical activity was good, so they said just to keep drinking water. I tried eating that night, had no appetite, but managed to eat two granola bars and oatmeal. today i still feel not 100 percent, and i dont have much of an appetite still. Ive drank enough water though where if it was dehydration id assume id be better by now. I also havent been pooping right for the past couple of months, so im not sure if maybe i have some kind of parasite like tapeworm or something. Although when im playing video games or out doing something physical i feel fine... just cant quite figure out what could be wrong. seems mostly like something is preventing me fro hydrating.