I frequently use HCG for LPD support. On the cycles that I take 2000iu on 3,5,7,9 post peak I have been known to still have a shadow of line on a peee stick around 14 dpo. On the one cycle that I had my blood levels check, my hcg was 6 at 19dpo, AF had started on 17 dpo that cycle. Maybe something that cycle actually tried to implanted but the Dr seemed to think it was left over from the hcg shosts.
Lately I've been doing 6000iu as a trigger, and then using 1000iu on days 5,7,9 & 11 post peak By 14dpo I can no longer see a second line.
They claim about 1000iu leave your system a day but I'm fairly certain I take longer then that. What doses are you taking and on what days?