I have an on average 33 day cycle, ovulate late around day 22. Day 1 of my current cycle was Oct 12. Ovulated on Oct 31. Should have started my period on Nov 11. Four days after I should have started I'm having what appears to be implantation bleeding. Matches description and color. Very light cramps. Going on 1.5 days of this off and on. Got a positive at home test yesterday before that all started. Had appt today at doc (due to cramping & off bleeding) urine test was negative there. Waiting on blood results still. Is it possible to have the late implantation bleeding giving me low hcg levels?? Any advice welcome. This would be my first pregnancy.