nausea and dry heaving

Help!  I have had nausea for 6 years and this past week the nausea has become intolerable and all day every day. For an added bonus I am now dry heaving. I recently had a sonogram and blood work that showed everything in my abdomin (abdomen) was fine.  I too was told in the beginning it was in my head.  put on anti depressants and what not.  They made me sicker.  Now I'm on zofran and lorazapam.  Still nauseous and dry heaving.  Going in for an upper gi on Monday. Could there be a cancer that is being missed?  My body is telling me there is something wrong and the docs can't seem to find it.  Don't know what to do next. Is there anybody with the same problem???