Period problems

I know this isn't the right group for this but I posted it in the period group two days ago and has no response. I would really prefer to not randomly start bleeding with no warning, thanks.

Okay, so about a week and a half after my last period I had about three days of spotting, but really really light spotting, it didn't even leak through my pant and I have no idea it was even happening. Now, I am four days late on my period. As far as I know, I haven't been so overly stressed to delay it, and I know I'm not pregnant because I haven't had sex in over 6 months and I've been bleeding regularly since then. So I'm questioning, did my period get randomly thrown off somehow? And should I count those days I was "spotting" as my last period? Has anybody else had similar situations? My period is usually pretty regular which is why I'm questioning if it skipped. Any comments would be helpful, thanks.