Hello i recently was taking antibiotics and now i'm having horrible stomach pains what could it be?

Possible reaction: to the antibiotics. Some antibiotics are more upsetting to the stomach than others. The macrolide antibiotics can sometimes cause stomach pain (erythromycin, azithrmycin, clarithromycin) and the tetracycline family is also notorious for stomach pain (doxycycline, minocycline). If you are having bad diarrhea, you should also be screened for C. difficile. On the other hand it could be unrelated!

Could be many things: This may have nothing to do with your taking antibiotics, but if related it would be because antibiotics kill many of the trillions of friendly bacteria in our intestine but do not kill yeast or many of the unfriendly flora, creating an imbalance of the microbiome that can have long-lasting adverse consequences. Take quality probiotics, but you might have an ulcer, gallstones etc. so see your doc.