Food poisoning? stomach flu? help!?

ok, so starting yesterday morning, i had the worst stomach ache and felt the need to sleep all day. i was dehydrated, so i drank water all day, and i had, and still have, dark green and watery stool on day 2. My stomach still hurts, not as much as yesterday, and i can actually eat now, but I have yet to vomit since the beginning of all this. The night before i got sick, i ate Taco Bell, and slightly recall part of my burrito being cold. So do I have a case of food poisononing? or a stomach bug? I haven't thrown up, so that's the only thing that's skeptical, and the pain isn't unbearable, but it's enough to make me frustrated. If anyone can help, that'd be appreciated!