Implantation bleeding or early period?

My cycles are ALWAYS 28-29 days. I always get premenstrual cramps a few days before AF.

This month I started bleeding on day23. It caught me off guard as I hadn t had any of my normal warning signs. The bleeding was pretty light at first, but enough to leave a stain on my underwear, and I had slight cramping. The cramps got worse, but were manageable and not as intense as my usual AF cramps (which require pain meds). The bleeding stayed pretty heavy for the next 2 days and seemed different than my usual AF. The first couple days of AF it s always bright red with a few clots. This, although the flow was quite heavy, was a lot more watery, the color more pink and no clots at all.

After those two days the bleeding became lighter and it became more brown. This went on for 4 more days. I finally stopped bleeding yesterday.

I wasn t tracking my ovulation this month so don t know exactly when it occurred. But if ovulation happened when I believe it should have, the bleeding would have started around 8dpo.

I took a pregnancy test yesterday (the day I was originally expecting AF) and BFN.

I don t really feel pregnant, but have been extremely tired the last few days, very hungry and thirsty, and have had waves of nausea here and there. I ve read a lot about implantation bleeding and most info says it shouldn t be heavy at all. But part of me is wondering what is going on. It is NOT normal for AF to come 6 days early, nor did this bleeding look or feel like it normally does. Thoughts?