Hcg levels not doubling?? Help

I got a blood test and my levels went up but didn't double. Anyone know what that means?? I'm freaking out. Won't hear from dr until Monday! I almost 5 weeks. I'm 37, and last week had a little bleeding for 6 days no clots no pain. Went in on Thursday and again on Saturday and my levels went from 2777.1 to 3109.1.