My Period Is 6 Days Late😬

I know you guys are about to call me dumb or something...

But I had sex a while ago and i got periods between those times. But all of a sudden now, I’m not getting it (well, im 6 days late) I can’t be pregnant if I got my period last month and I had sex in January right????

There’s obviously other reasons...i just don’t understand why my period is late, it’s always on schedule.