Now there are two ways to look at it. It can be truth or just an excuse but either way, you should be done here and seriously consider moving on. That'll be in your best interest. Don't hang to something so inconsequential, okay? Okay.:)
Sorry, with these answers, it's more helpful to read them as "I don't want you to be my girlfriend". Most often it's not a matter of not being ready/not be looking for a relationship, it's just a polite way to reject you. But congrats on having the courage to ask him! Having asked, even if it doesn't go well, has the huge benefit that now you know it isn't something that can happen and you are free to move on! So don't ruin the only benefit by tinkering his words with wishful thinking, take some rest and then be open to someone who will say to you "Hell yeah I want you as my girlfriend!".