Miscarriage?

On Sunday night i had a gush of blood come out as i was driving home. Enough to soak my underwear. I had a shower and there was more blood with little specs in it. I then began having very painful cramps worse than a period. A few hours later i was passing about 1-2cm sized clots and grainy like clumps. The cramps passed after some pain relief. On Monday i was getting cramps every few hours and more clots passing. We called our IVF place and they were confused why we didn’t go to the hospital and didn’t really say much. They booked us in for a blood test. Bloods came back as if everything was fine and HCG at the right levels for 5 weeks. They said we could go to our original blood test “if we wanted to” on the Friday. They said everything was normal and didn’t really explain what all this blood was or pain i went through. We didn’t really believe everything was fine even though they said “i know it’s hard to believe but you are still pregnant”. We did the blood test Friday and HCG levels had doubled even though blood and clumps were still passing just at a slower rate. For this test they didn’t even call us for the results. We called them asking what it was. All they said was “doctor said it was good and everything’s fine”. We have out 6 week ultrasound booked in on Tuesday. It’s been a roller coaster of a ride emotionally and still don’t really believe we are still pregnant after all the blood and massive cramps.

Is it possible for the body to still think it’s pregnant and double the HCG after 5 days after miscarriage?

What was all that blood?

Why was it cramping so bad?