Trapped burps that need forcing? When I try force this horrible stuff comes up?

I'm always burping, and most of the time they're very tiny that need forcing to pass... Other days, like yesterday, I was burping normally, but still a lot. However, today, I feel something come up my throat, it feels like vomit or something, and sits at the back of my throat.... I try forcing because I think it's a burp but then this horrible liquid like stuff comes up a little. It doesn't feel acidic or burny most times, only on the rare odd occasion it will. But usually when that stuff comes up a little, I usually get this horrible vomit taste in my mouth. I'm pertrified of vomiting, so I avoid it and try my absolute best to hold it in. I've had this problem for like 2 years now, but it's only recently got worse. Years ago, I never used to get that vomit taste, nor did I have to force burps... I'm really scared because I'm only 18 and worried that it's vomit trying to come up... Thing is, usually, I have no other symptoms with it. No stomach aches, no nothing....... Some days I get a burny achy like sensation at the back of my throat and chest as well. It feels more painful than burny though, but I can definitely feel a burny sensation along with it. Does anyone know what this is??? My doctors have been no help... They think it's all anxiety and that I'm really 'fine' but how can this all be anxiety? When I can actually feel something come up into the back of my throat? Funny enough, I haven't EVER vomited from this, although sometimes I feel like I might which scares me. :( Also, some days, my nausea is absolutely appalling. I have to go lay down to rest for a while and then when I rest for like, an hour or so, it seems to disappear. I'm guessing that's to do with anxiety but I just don't know..... I've tried lots of anti-acids like Omerprazole and Gaviscon which had no effect.... I'm feeling depressed because of this..