I.G.
I think you are making the right decision! You have noticed right away that you can't handle the responsibility and it is SOOO much easier to rehome a puppy than an older dog who has not received proper training, because you could not give him the time he needed.
If you got him from a breeder, please call them and ask them for assistance. Many reputable breeders will either take a return (no refund though...) and rehome the pup for you, or they may be able to simply help you by pointing you to people who might be interested.
You can also contact a local rescue for your breed or simply put an ad in the paper (I would not use craigslist for this!).
The sooner you rehome him, the better for everyone involved!
Good luck!