implantation or early AF....so confused??

randab04

A little background info: my lmp 4/3 (that was also the day I  took out my nuvaring)...bd on 4/14 & 4/15 ... O'd around17th ( i was on antibiotics and didnt put mY ring back in talk to dr and seen him he said I O'd). Cd 20 (4/23) I started to spot light brown then the following 3 more days it was either dark (almost black) brown or reddish brown. Then stopped for one day now today I noticed that when I wipe I see a reddish pink color and i have to pee a lot. AF is due on May 1st (3 days from now). Idk if it bc I just stopped bc 3.5 weeks ago or if I might be pregnant. I know the only way to tell is wait for AF and if none then test. My question is has anyone ever experienced spotting for a couple days on and off within the week before AF due and ended being pregnant?? Although we werent trying i would be so happy if i was...thanks for your help!!!