CAN MARIJUANA DELAY YOUR PERIOD?

So I haven't smoked weed in 3 months and I finally started up again. Back to the usual bowl, sometimes when I wake up, but mostly before I go to bed, it helps with sleeping. Now, my boyfriend and I had sex 4 times last week and I was supposed to start my period Friday. Now, he NEVER finishes inside me, and we never finish with the condom on, I usually "help" and we do this for precautionary reasons. Now, sometimes we do start without a condom and go for about 2 minutes then put it on. I was supposed o start Friday which was 2 days ago. I have had very minor cramping, slight blood but not enough for a tampon, and white discharge. My boobs are not sore, no bloating, my back does hurt, no fatigue or nausea until I start crying thinking I might be pregnant. With all this being said, is it possible that my period has NOT started due to the smoking? Or is there a chance his pre cum has fertilized an egg?