Help, just help

I have been on a progestin-only pill a.k.a. the mini pill for over a year now. I can’t take estrogen birth control because I have migraines with auras. I had a period when I first started taking it, then I didn’t have one for 11 months, then I got one for a week, a month later I got another for a week, a couple weeks later I got one for three weeks, a month later I got one for a month, and I was off of it for a few days and now I’m spotting pretty bad. I had sex at like 2 A.M. the day before last and woke up at 9 A.M. to some very light spotting but nothing else throughout the day. My boyfriend said he accidentally came in me a little bit when we had sex. I also accidentally took my pill 38 minutes late (very, VERY unlike me but I had a long night and was tired 😅) yesterday morning. I wake up this morning and am spotting pretty bad and have mild cramps. Are these implantation symptoms? Should I take a Plan B? Is it too late to take one? I feel like since I’ve been on birth control, especially this birth control, for so long that the chances are low but then again I don’t know. What should I do? What do you think is going on? Could this really just be my irregular bleeding that I’ve been experiencing, specifically for the past 6 months? Please help.