You also could have a stomach virus. The same type of symptoms are common with that. Try the lactobascilus. But also try to take in as few foods that are hard on sick stomachs. Try to avoid heavy foods, and dairy products. Best way to go is BRAT diet for a couple days: Bananas, rice, applesauce, and toast. I know, doesn't seem too appealing, but these foods are easy on your belly (even the applesauce)! And simple additions to this diet include tea and yogurt... Try to stick with a bland, clear liquid diet as much as possible too; water, clear FLAT (sugar free) soft drinks, broth, gatorade type drinks, or pedialyte. Easy for the stomach, and still keep from getting dehydration. Don't think you have to cut out ALL other foods, just try to avoid anything real rich or sugary, or heavy with fats or carb-loaded. Hopefully that helps. I of course, don't know your medical background, so can't answer 100% what would be safe for you, given your history. BUT. Maybe put a call in to the nurse who works with your family doctor and ask her to help you decide what would be safe for you personally. Feel better soon.
Which antibiotic were you on? It may just be intestinal irritation/inflammation from the antibiotics. It should subside. If it gets much worse see your doctor as some antibiotics can irradicate your normal gut flora and allow other bacteria to take over such as a bacteria called Clostridium difficile which has a toxin. I don't think you have that yet. you get about 10 bouts of diarrhea a day and bad cramps etc. It usually develops within 2 months of taking Ciprofloxacin, Clindamycin and some other drugs. You may want to try to eat two yogurts day to start (that have live bacteria such as bifidobacteria or Lactobacillus sp.). You can order some probiotics or get them but eat the yogurt in the meantime to get your intestines repopulated.