Period after sex

Okay so , I’m 18 years old and I’ve been having my period since 13. I have iron deficiency anemia so it causes my period it be very irregular ; that and I’m always stressed and I’m young. Last month I had sex on January 4th and I started my cycle the next day. As of right now I’m ovulating but my next period isn’t supposed to start til February 1st. Today I had sex and moments after I felt cramps and I started bleeding. It’s not a lot of blood but it’s spotting ; is this my cycle , or am I just spotting?? Pls help !!!!