Throwing up in the middle of the night.

I am 19 years old and have been suffering with this problem for quite some time now. What happens to me is, every 2 weeks or so, ill randomly wake up in the middle of the night with a terrible stomach ache, not being able to go back to bed. Then, at the most 20 minutes passes, usually it happens right away, I find myself ruunning to the bathroom where I throw up only once. Here is the weird part, after I throw up (brush my teeth and clean up), I go back to bed feeling totally normal and being able to fall back asleep fairly quickly. Ive searched all over the internet but have not been to a doctor yet because it doesnt happen everynight and I have no pain afterwards or the next morning. So far ive found the most common reply to this problem is acid reflux, but I have never had heartburn a day in my life so I dont think its that. Please, if some one has any sort of idea as to what it could be, please let me know. Although it doesnt cause pain, throwing can be very uncomfortable, especially in the middle of the night. Thank you.

No, I havent been to a doctor because it doesnt happen every night and I dont feel like its disrupting my life. It only happens maybe 2 times a month.
Thank you though. You think it could be acid?

Usually the food is fully digested. Im not normally a late eater so, the food is digested, the majority of the time. But no, ive never had heartburn before so thats why I figured its not an acid problem. Ill probably end up going to the doctor next time it happens so ill be able to tell what exactly I ate and when. Thank you (:

I know this is a little late, but I found your post while doing some research.. I've been having the same thing happening to me and I was wondering if you ever went to the doctor or found out what it was? Thank you!