I got pressure and trembling in my lower part of my body what is that?

I got a preg test and it says no (does RH- factor make it no), I got trembling in my belly all the time I put a ash tray on it and it trembles, and I got pressure in my lower area, i can barely sit or bend over, I went to the doctor and they say I'm ok, but I can't seem to take the way im feeling as ok...does anyone know or had this before?