How do i know keeping it is the right thing?

It doesn't sound like it is the right thing for you. I would give it up for adoption since it doesn't sound like abortion would be good for you, either. It sounds like you'd feel guilty. Adoption allows you to carry it to term and give it to someone who will love it and cherish it. You may also be able to visit or participate in the baby's life. Stop having unprotected sex until you're ready for the consequences.