HCG did not double

I had a couple blood tests and my levels barely went up within the 48 hrs. Did anyone here have a similar experience and everything turned out fine? I've had 2 previous miscarriages and I'm so afraid it's happening again. I'm just so frustrated!

UPDATE: I had my 3rd hcg test and it actually declined. Doctor said it's a definite miscarriage! Sooo frustrated!