Pregnant?

So I recently had sex with my boyfriend on Valentine's Day and we used a condom. I'm not on birth control, but the last two times I was okay. My ovulation period is over, and my period is soon. I'm super irregular, my "normal" cycle length is around 40 days. I'm very nervous, but my boyfriend thinks I'll be ok. I'm supposed to start today but I'm anxious and I think I stressed myself to be late again. I'm not ready for a baby, I just turned 18! 😭