I blacked out, felt dizzy and fell?

this morning I woke up and went downstairs and told my mom I didn't feel well. She said to eat something and take my medicine. so I went to the kitchen and got out my medicine (I'm on lexapro, nexium, karafate, klonopin and erythromycin.) I started walking back to the living room before taking my medicine and felt really dizzy. I couldn't see and my legs were wobbling as I tried to walked and I fell. about 15 seconds later I gained back my vision but felt weak. what could cause this?