HCG/progesterone numbers

Hi ladies, I believe I ovulated late this month (around CD21 or so) out of a 35 day cycle. Anyways, I received my BFP on 12 DPO and had my first HCG draw on 13 DPO with 37 progesterone and 161 HCG. On 15 DPO, my HCG was 311. It almost, but didn't quite double. I believe I am somewhere between 3-4 weeks (when my numbers were taken) as I just missed my period on 15 DPO. I am nervous about this number, as well as, I'm not feeling much of any symptoms except insomnia, some cramping, and random/mild bouts of nausea. My breasts don't really hurt and have gotten enlarged just a little bit. Can someone please give me a success story with HCG levels that almost but don't quite double and limited symptoms this early on? 
I had a MC last January at 14 weeks and those levels were super high in the beginning and I had a chemical this past September and those levels were very, very low--20 HCG and 4 progesterone and they dropped the second test. 
Thank you for any positive feedback! I'm a nervous wreck.