Did I have a seizure? I was walking down the street with my boyfriend and my knees began to buckle and lock so?

I was walking down the street with my boyfriend and my knees began to buckle and lock sort of. It felt as if my legs were like spaghetti. I stopped walking for a sec and I was fine then as we cont. I no longer could walk. My back began to bend backwards, it was so crazy! He picked me up and my body felt limp. He put me on my feet and as I tried my hardest to walk my back began to bend backwards further and further I cont. to talk to him but I had no control over my body. We were almost to our destination when it felt like I completely lost control, he set me down on the bench and I bent all the way backwards, legs locking. I took a deep breath and he said it was time to get on the bus. On the bus i couldnt stop sticking my tongue out and the next 45 min. it felt like I was gagging myself with my tongue. I looked up at the sign and I couldnt STOP LOOKING UP. It was crazy like I couldnt stop looking up. Every time I would think I would look at the ceiling. I couldn't stop looking up and I couldn't stop sticking my tongue out. This is basically what happend. I wke up the next day and it felt like some one beat me up. I am prescribed Keppra but I hadn't been taking them. About an hour before this happened I took 2 Risperadals which im not prescribed. I have had mini seizures before that's why I was prescribed Keppra.