I had unprotected sex 6 days before my period, next period was on time and normal but I'm spotting

Hello, I had unprotected sex on the 22nd day of my period which is usually 28 days I got my next period on time and was normal apart from the fact that I didn't have pain. Then on the 18th day of that period I started spotting for 7 days it was quite heavy so I needed to wear a tampon or at least a panty liner it was sometimes brown and sometimes bright red. I am 40 years old. Can I be pregnant? I'm one day late.