I'm so confused

so i'm planning on seeing a doctor for this, but for a while now (like almost a year now) I've had this odd problem. When I eat I can only eat so much before I literally feel sick and when I take a bite I start to gag and have to force that bite down before I stop. I can only get a little way through my meal before it starts to happen and shortly after i'll feel hungry again but then eat okay. At first I thought it was just my anxiety disorder preventing me from eating (When i'm at conventions or stuff like that I literally can't eat at all) but I've noticed this just happens. I don't know, does this happen to anyone else???