Pregnancy/Period Question

So I’ve had my period for about a year and a half, it still hasn’t regulated completely but I usually get it every 2 months. Mine is 20 days late but I haven’t done anything past kissing with my boyfriend, and because I’m super paranoid I don’t share towels with my brother or dad. I was sick for a couple days with strep and play sports 2-3 times a day but that hasn’t stopped it before. There was a period of time (1-2 weeks) that I was incredibly stressed but the past week has been better, does anyone know what could be wrong?

This is highly, highly unlikely but how long after sperm exposure do you start seeing pregnancy symptoms?

I haven’t had sex or even made out but just in case, I feel completely normal🤷🏼‍♀️