Horribly low HCG Blood test at 13DPO, has anyone had this?

Kelley • 30, due with 2nd child 2018! Two prior miscarriages.
I got the faintest positive on earth, so I went to my fertility doctor and my blood test came back at only 11HCG. I know this is not great at about 13DPO. Having levels redone tomorrow but has anyone experienced this?  Did you get your period shortly after or did it progress?  Thanks ladies!