Concerning numbers

Jenn
So since I've had 3 previous miscarriages I have to go do the blood tests and check my blood levels every 48 hours. So far they have been double but two days ago it was 308 and today it's 575. The doctor said its a little lower than he wanted to see. Is it becUse it hadn't been 48 hours? I went at like 46 hours. Should I be worried? I gotta go again Monday. I really was hoping this  would be my rainbow baby? Any advice would be greatly appreciated. Thx