May not seem like it now, but it's better that things have ended sooner than later. If she left you over something you have no control over, something that can improve with time then she isn't worth yours. It's just going to feel like shit for a while but it will pass. As for your stammer, how bad is it? Mine as a child was fairly bad, but with time it gradually got better, then by my late teens it was almost gone. I'm approaching 30 now and sometimes I have the odd day where it creeps back in but for the most part it's gone. A coping method I used was if I thought I was going to get stuck on a word, I'd pretend that I wasn't going to say the word but then at the last second before saying it I'd actually say it, it was as if I was tricking myself into not getting stuck.