Girlfriend's sister is pregnant with my child?

you might as well try to make a life with your baby's mother- if she was good enough for you to lay with and ruin your relationship- she should be good enough to be with and with a child you two are gonna be stuck with each other no matter what- you have a great responsibility now- hopefully you man up and at least be a good father to your child- don't let your child suffer for your mistakes- I wish you the best of luck