Anyone else having HCGs drawn?

So I'm due Oct 18 (6 weeks pregnant today) and I've been spotting every day since Jan 29 which worries me because I had an ectopic last March and I spotted every day with that one as well. My Dr has been monitoring my HCG to make sure it doubles every time and so far it has (it didn't with my ectopic). This time at 5wks=247, 5wks 2 days=595, 5 wks 4 days=1322. I got it drawn again today but no result yet. It still just seems so low to me for 6 weeks even though it is doubling. Thoughts?