na you shouldn't have done this, but you did, and you can't turn the clocks back. Really you should hope you aren't pregnant at this time to save all the drama. And you can get pregnant anytime. So it would be difficult to determine who the father is.
You ought to think more carefully before engaging in sex, you gotta think about std's etc.
It isn't fair to the baby either, if there is going to be one, babies need to have stable homes, and both parents in its life. having a baby needs to be a mutually planned thing between two people, not something to lure a man.
Please I hope you are not pregnant and I tell you to quit playing with fire. Raising children without a dad is not easy. Single parenthood is not easy. Having a baby changes your life forever. It is a huge responsibility.
I know because I was a single parent. It was not easy. It could have been prevented if I was more careful and not so stupid. I advise you to really think about your future and stop messing around.