it could be af - it sounds a lot like wat happened to me when i m/c. i bled and then it went to spotting so thought it was stopping....then a couple days later it got heavy and only lasted 4-5 days, so i guessed it was af, 4 weeks later af appeared on time so that is what i assumed.

also with my chemical pregnancy my levels were 10 and i was bleeding

hope it helps a lil sweety
xoxox