6 Weeks late and negative home tests

I am now 6 weeks late with my last period on 6/17/11(which was very light and lasted half the day) didn't have anything after that. Ever since taking out the IUD in October 2010 I have had my period exactly the same time every month. I have had all the pregnancy symptoms from cravings, fatigue, major lower back pains, nausea, tender breast, stomach growing(looks like i'm pregos) and once in a while when laying down, i feel little movements in my lower abdomen. My stomach is even getting more firm. I also can't lay on my stomach anymore. I've taken a home test once a week since i was 2 weeks late and they are all negative. I've gone to the doctors and they keep telling me to come back in a few weeks. I have asked for a blood test or an ultrasound and have been denied both times. BTW this would be my 4th pregnancy and I know how it feels to be pregnant and I definitely feel pregnant. According to my calculations if i'm right, I would be 10 weeks pregnant so i'm confused as to why the doctors wouldn't do an ultrasound. I don't have insurance but i've been going to the free clinic. Any suggestions??