Random Vomiting in the morning?

I woke up this morning and just randomly threw up. The day before I just had two waffles for breakfast, then I went over my friend's house and we ordered Domino's about an hour later. I had two slices and four hot wings. Later that night I had two more slices around 8pm and I didn't have anything else that night. I stayed up until 2am and that same night Ended up crying really bad over something but I doubt excessive crying can cause vomiting. Then, this morning I woke up at about 8am to go to the bathroom and I felt a little funny but it felt like gas so I just went back to sleep. At around 9am I woke back up to use the computer and by the time I went to lay back down I had some really bad nausea and gas. I got up to go to the the bathroom again and took a pretty good bm (excuse the bluntness lol) which made no sense because I hadn't eaten anything since 8pm last night. I took some May Lox, then around 10am I told my mom and she said that I just need to throw up but I figured I was just hungry because I only get nausea when I'm hungry and I haven't thrown up since I was 11 (I'm now 18). So I had barely half a bowl of cereal because I was't hungry. Mom told me to take alka zelser but she said It might make me throw up because that is what happened to her. Sure enough, two mins later, I threw up. It was completely clear. Of course my mom asked me if I am ually active with my boyfriend and am I possibly pregnant, which I'm not. Even if I was, I take birth control for my period which I forgot to take yesterday -___- and I have had with my boyfriend (ik -___-) but nothing involved any bodily fluids, so what do you guys think??...