Pregnancy from foreplay?

[cw9251]

I had a one night stand with a guy I know three weeks ago. There was no penetration at all, his penis was never in my vagina. In fact, there wasn't any direct contact with between our bits, it was mutual masturbation, kissing, fondling. I never fingered myself, just rubbed my clit while he fingered me. I never saw him touch his penis directly. He masturbated me first, then we shifted position and I did him. He finished on my boobs and I got up and washed my hands with soap and water. Then dried them on a towel and used that towel to wipe the semen off my chest. Then wet the towel and dabbed my vulva area with it. That's what has me freaked out. I'm paranoid I might be pregnant from this. I have always had irregular periods, so being 'late' is not unusual. I get 'anything is possible' but, is this really something for me to be freaked over??? I have anxiety issues sometimes and I think this is one of them.