Sex q help !!

I had unprotected sex for literally 10 seconds he didn't cum inside of me or anything it was a stick it in then take it out type thing and that was about 3 days after ovulation so today got my period right on time and been having pms kinda bad and cramps like always but my period is really light which is not my normal cycle normally even from day 1 it's a medium to heavy cycle I started freaking out even tho I knew I probably wasn't pregnant but I started researching implantation bleeding and it said the day I'd prob experience that was August 30th (I ovulated on the 21st of August my cycle is very regular 32 days and my last period was August 3rd-8th if that helps ) but the dates in September for implantation were very un common so I felt at ease like this was my actual period and I'm not pregnant it was normal kind of medium and bright red when I wipe and when I went in the toilet there wasn't as much blood as normal but there were some clots earlier today like always which don't occur in implantation and the color wasn't light pink or brown there was not really spotting so I think I'm good I just need reassurance I'm confused why it's so light there's barely anything in my pad I'd like to think it's because I'm so stressed but opinions please HELP!!