Implantation bleeding

I had my period about a week ago. My SO came inside me three times in a row (within two days) after the last day of my period.
Today I have noticed when I wipe after going to the bathroom the toilet paper is a bit red. Not really spotting but you can tell there is some light bleeding. So I went inside and yes there is some extremely light bleeding going on. I am feeling tired but that's not unusual for me so I'm not counting that.

Could this be implantation bleeding? Has anyone conceived the week after your period?

Possible if you have short cycles

Yes this cycle was about 3 days long maybe 4

From one period to The next!

Oh no I meant that it lasts that long usually. I honestly don't keep up with it as well as I should. I start around the 8th of the month and it lasts about three days. So by the 11th or 12th of November, I was off of my period and we had unprotected sex. It is the 17th and I am feeling mild cramps and spotting. It got heavy enough for a pad, but only a few spots on it. I didn't have bleeding with my daughter.

It could be that maybe you're cramping and spotting from ovulation? it's rare but it happens...