HELP!!! I Am Pregnant With My Step Brother's Child

UNEDITED!!!

We've always treated each other like blood siblings, or should I say I pretended to treat him like that, because I don't have brotherly love for him. I'm in love with him (my step brother). Every time his gf came over for a visit I got jealous and said nasty things about her and even tell my mum and step dad that they should tell my step brother to dump his gf cause she's no good. But that fell on deaf ears. So I did something that broke them up. When I was successful inbreaking them up I was so happy cause nowI could seduce him. I started wearing very short skirts and shorts, and I used to drop things on the floor on purpose so that I could bend to pick them up. I also started coming out of the bathroom only wearing a t-string. One day he fell for it and we started having sex and we never looked back ever since that day, sometimes we even made love at our parents bedroom when they not home. Now the thing is I'm pregnant with my step brothers child, what shud i do?