Sorry to hear you got messed up mate, but I have to agree dogs do not attack for no reason, may be worth your while if you plan on ever having another dog to see what may have caused this so you can avoid it in the future. One thing to consider is get a female pup, you have a lot less headache dealing with dominance issues as she will see you as the alpha if you handle her training and punishment.
I have only ever had to put one dog down of mine and I did everything I could before that decision was made, long story short while the dog was still healing from a fight with a raccoon which tore my pups ear up, he snapped at and almost got hold of my 3 year old nephew and the neighbors boys. I was advised by the vet that at his age and current state it would be better to let him go, so I did.
I also have trained a number of dogs in my time and one thing I always recommend to folks that are looking into getting a pup is look up a man by the name of Richar A. Wolters, he wrote Water Dog, Gun Dog, Game Dog, and Family Dog it is by far the easiest to follow training with the quickest results I have ever seen, and a number of current dog training experts use a variant of his research and practices.
All that aside I hope you heal up and have no lasting issues from this.