Most Helpful Girl
I think the best thing you could do is find him because he has the right to know that there is going to be a child of his out there rather than 18years down the line your child going to look for their dad.
Are you 100% it is this guys, as that is important also. I don't like to assume. Something you need to keep in mind is that you have decided to keep this baby and he might not want anything to do with it at all. You need to mentally prepare for that. However he might surprise you and want to be involved, and if not him his parents you can't assume how it is going to do but the main point here is he needs to know.
As for your parents, might be worth talking to them and tell them about your plan to get in contact with the guy and go from there. Just be the adult and have a frank conversation but you are trying to make the decisions that you feel are right for you.
Most Helpful Guy
No point telling you what you should have done 6 months ago... but seriously don't take mistakes as unerasable parts of your life. You should have asked for guidance from friends and family right at the begining.
But it's not too late. Talk to your parents. I mean eventually you will, so save yourself the stress. You're still their daughter, after all.
About seeking out the father... up to you, in all honesty. There is no telling how he will react to this. But I think I agree with your decision. Tell him about this, and if he wishes to support you, well and good. If he doesn't at least it'll be a clean break and you can stop worrying about that particular matter.
Whatever you do, don't lose your strength :). All the best.