Have you been to the doctor yet? This does sound serious to me. In some ways it sounds like gastroparesis - where your stomach just doesn't contract enough to empty on its own. This would give you the reflux and the very full feeling. The liquid bowel motion though sounds more like constipation - a very solid back up somewhere that only liquid is getting around. This may also cause you to feel nauseous, and your stomach not empty properly. BUT - whatever it is, it isn't something you should be fooling around with. Even if it has come right now, I'd still go off to doctor and report as clearly as you can what happened. You need to know what to do if it happens again.