My this month periods are late by 5 days usually I hv late periods by 2-3 days and I had regular and proper periods for last 2 months, I had sex I'm January mid and that was safe just worried that can't I be pregnant

I doubt it, but with a few billion women in the world, just about everything imaginable has happened, including having periods while pregnant. They aren't periods, just light bleeding. Many women have just one.
As far as 'regular' periods, it is rare to be like clockwork every single month, and you will change as you age too.
Why are you taking risks and worrying instead of using birth control?