Terrible almost all water diarrhea.. what do I do?

I think I've had a weird stomach virus the past couple days. I ate a shady lookin' burger at a bar and then got so sick the next 2 days after. I finally felt better today and then bam! Horrible diarrhea! It doesn't hurt I can just hear my stomach gurgle and I have this awful, terrible smelling diarrhea. It's like my body's out of stuff to use now so it's just using pure water. I've been taking Pepto Bismal 30ml every half hour for an hour and a half and it's not stopping or even slowing down. About every ten minutes I have to get up and go to the bathroom... Any ideas how to stop it?? I bought some Imodium but I'm scared that if I take it it'll keep it all in and none of the bad stuff will get out..