Also sounds like things moved a bit too fast with you guys, in 5 months discussing kids names and buying houses together is rather speedy. Maybe he suddenly felt suffocated, despite the fact he loves you.
You can't force his committal... if he decides he does want a relationship with you then great but don't just hold out and wait for him, don't base all your happiness and decisions on his answer. Leave it a few weeks, if nothing makes progress then accept its over and move on. Next time try not to move as quickly, as right as it seems.
Hope you feel better soon
