What Causes Dizziness And Nausea Along With Stomach Pain?

I was in the ER Sunday for what I believe was food poisoning from food that had been sitting on the stove for hours. I received medication for the swelling, stomach pain, and nausea. The medication made me dizzy, weak, and sleepy. On the third day I felt better and stopped the medication. I kept drinking lots of water, Gatorade, and Electrolytes. I started to slowly eat bland foods. I felt fine. I then ate regular meals for 2 days. The next day, I felt weak, had stomach cramps. and small hard stools. I took a stool softener too soon, because in an hour I had soft stools, then diarrhea. I took diarrhea meds to stop it. I noticed red blood in my stools. What do I do now?