I need ur guys' help

Ok so March 21st I went to the beach, and for some reason the next day I had stomach flu like symptoms. I had puked and had diareaha. Then the next day I was perfectly fine, until a few days after that, no matter what I ate I kept burping this nasty stuff up and then once again the following week I got sick again. Anyways it's been going on since the 22nd of March, I can't get in to see my docotor till Monday and the receptionists just tell me to take pepto bismol. I haven't taken it yet since I haven't had a chance to buy it. I thought maybe it was something I was eating since I was constantly going to McDonald's of del taco but since I cut that out it can't possibly be that either. Idk what to do anymore. I can't handle being sick like this, it makes me feel like crap for days then I have a "sick day" and then I'm ok for a day or so.