I took the 2 pills named azithromycin a few hours ago. and about 20 minutes ago i drank a small dose of pesto bismol, and feel much sicker than before?

Azithromycin: Azithromycin often causes gastrointestinal problems like pain, nausea, cramps, and even vomiting -- especiallly in the fairly large dose you took. It's unpleasant but not harmful and will clear up soon; you should be fine by later this evening. You could try a different antacid, like Tums, Rolaids, Maalox, etc. Or eat a small meal.