pregnant after fluctuating test

I have posted on here a few times over the last week with fluctuating hot results blood draw a week and a half ago my level was at a 20. having horrible cramping but no bleeding. af 13 days late. went back to Dr today. repeat blood draw showed 1265. ultrasound only showed gestational sac that measured 4 weeks 3 days. but got this morning was completely negative I think. thoughts?