I just threw up.. WHAT THE HECK?

I'm 14 years old, I just started taking a prescription to help stop me coughing mucus stuff up because I've had it for almost a month now. I took my medicine as usual this afternoon with some food. I was just sittin here hanging out with my laptop, next thing I know I feel nauseous and am running to the bathroom to throw up bile! I feel fine now, but I don't know why that happened. Maybe I didn't eat enough food with my pill?