I’m Really Worried! Please Help!

Hey everybody!

I’m leily and i’m 19.

My Cycle is 28 days i guess (My period usually lasts 4/5 days)

I Had sex for the first time last week, The day after my period ended. (i Have had done some stuff w my BF of four years but i never really had “Sex” Or penetration) but this time i’m really worried i might get pregnant from Pre-Ejaculation or the Semen that was on my belly but i washed it away in the bath so maybe it made its way into my Vagina somehow.

I Have been taking birth Control for 3 years and it had been 3 days since i started a new pack that day.

I just wanna Know if there might be a chance of me getting pregnant.

sorry for my bad english!

thanks!!