Urgent, advice please

My period started February 7th and ended on the 11th. I had unprotected sex on the 16th of feb. I took plan b the 17th of February. Got an early heavy period on the 22nd of February and it lasted 5 days. The day after my period ended I had cramps and am still having cramps. Yesterday I had a very very small amount of blood only when I wiped. (2 spots Dark pink) Is it possible for IB to still occur even after a heavy early period? My CM/ discharge was heavy Tuesday and yesterday but I have no discharge today and my CM is very thin and watery. I’m not sure when I ovulated and I know it’s usually 6-12 days dpo that IB occurs. Any thoughts? I took a pregnancy test this morning but it was negative.