Implantation or light period


So I hate ttc. My cycle was perfect before, now not so much. Last month AF was 5 days late. This month I had brown spotting a week after my positive OPK. DAY one was a brown spotting, day two was about one oz of period like bleeding (dark with clots, normal for me), and day three was brown spotting. I took a pregnancy test this morning but it was negative. Now I'm either 13 dpo or on cycle day 7. I swear, sperm is messing up my cycles! Oh, and I only had some twinges of cramps. I always have bad cramps.