38 Weeks Pregnant with sharp pains?

As of today I am 38 weeks pregnant. Last week my doctor said I "seamed to be" 1 cm dilated. Last night when I went to change for bed I got a severe pain right below my belly (kinda like where you would get cramps from your period). When I lay down, sit down, or just stand somewhere, I feel a lot of pressure and every so often weird vibrations traveling through my vaginal cavity. When I walk or bend over, even bend my knees down from a standing position or sit on the toilet, the pain i'm getting gets worse. Oddly, if I pee and kinda "push" I feel slight relief. I called my doctor and she said that I either pulled a muscle or i'm in labor but not to come in until i'm getting "unbearable pain every five minutes". I'v tried the whole bath thing, and laid down for three hours without getting up... Nothing is helping... Anyone have any idea what might be going on?