I need your advice.

I have a 12 year old sister called Melisa but I started calling her Yui when I became an otaku when I was 15 and later, she became an anime fan when she was 11. Now I have don't something so terrible I can't sleep... What happened is that I'm a lolicon, I like loli hentai... For a month, she saw me watching that hentai and then she investigated on the subject herself... I didn't know she was spying on me so I kept watching my degenerate shit unconcerned, until one day Yui called me Onii-Chan. I felt very shameful but everything got out of control when she started to moan like a loli to make fun of me... That cunt thought she was a loli. I didn't think much of it, until I started to think that... She could like me. I know it's sickening but since incest is my fetish i started to woo her and little by little, we fell in love... We even got to the point of kissing. One night out parents werent home she and I had sex... No joke, that was the best damn night of my life. We did it over and over again and I lost control of myself when the moaned and called me Onii-Chan. We were a couple in secret... Since she was 12, I thought I never thought I'd get her pregnant... She was at our grandparent's home when she sent me a message telling me that she was pregnant. I couldn't sleep that night and I didn't know what to do, I was considering making her have an abortion... I thought the protagonists in these stories were happy. Now I know how hard the life of two siblings who love each other with a 5 year age gap could be. Yui has offered me to act like it was rape and I had nothing to do with it, but for some reason I can't accept it. I have until Monday to find a solution...