Been waiting for this comment.

So are you adopted or is he not your biological father? Either way I am sorry

Well...that escalated quickly!

That's pretty vague and it doesn't make any sense.

OP, Damn! I can't even begin to feel your pain, but... Your dad had the courage to give you some of the worst news ever. Just because he is not your biological parent does not diminish his role in your life. If you both believe and care, you are family. The man who helped create you is looking for you, then maybe you could meet him with both your parents. You are loved and special to your folks. Keep that close in your heart.

I love the wording of this :)

The day you were so bad your dad stopped loving you

This is obviously vague for dramatic effect - and that works - but it would be nice if the OP could stop by and clarify. I would reiterate what is already said above: It's not the conception that makes him a parent. It's the years of being there and loving you and providing for you and worrying about you and helping you in a thousand different ways that makes him your dad. Arguably more so if he knew you weren't his biological child.

that's an awkward talk no doubt

If you thought he was your dad, he obviously raised you and took care of you... That's what a dad does, whether he's your biological father or not.