Pregnant but not?

I took 2 clearblue pregnancy tests about a week ago, both were very positive. Went to the Dr and had it confirmed. 2 days ago I woke up bleeding, I went to the ER and the Dr had blood work done blood test was positive for pregnancy. She also did a urine test. The urine test was negative. She said the blood is just my period, but my blood test was positive for pregnancy. My friends mom said maybe I had a miscarriage and the hormones weren't coming up in my urine anymore but they were still high enough in my blood for the blood results? I'm not cramping anymore and I'm bleeding on and off now. What do you guys think?