Hcg levels rising but not doubling

Vanessa
Hi everyone! I'm a little nervous since I miscarried back in April and I'm so afraid to lose another little one. I first went to the doctor at 5 weeks and my levels were 78 (7/31). On 8/7 by levels rose to 1623 and my most recent beta was 8/14 and it was 1750. I'm worried since they are not doubling. The doctor scheduled me again for Thursday 8/20. I haven't had any bleeding or major cramping at all. I've also had regular pregnancy symptoms like sore breast, frequent urination, and a small bit of nausea. I am a bit over weight so I don't know if maybe that has anything to do with it. (5'5" 215 lbs). Anyone have any experience with this? This ultrasound picture was from 8/14. The tiny spot on the upper left is where the doctor said the baby is.