The Wall

I've heard about this problem and figured it would just happen to other people. I used to run three to five miles every day and do just fine. But I have hit the wall. My legs just won't move past a half a mile. It frustrates the daylights out of me. I want to yell and scream and curse the world. How in the world am I going to run for my cousin in May if I can't manage to get over this hurdle. I was supposed to be up to a mile and a half by now. I wanted to wow my friend when we return to work. But right now, I am running in two shifts - am and pm. I don't know if I am not eating enough carbs or if I need to lift weights on my legs. They just get tired. They don't hurt; there's no ache; they just kind of stop moving the way that I want them to. My lungs (which I was worried about since I quit smoking) are doing great. I think I am going to increase my carbs first. I have discovered the joy of scrambled tofu and as a result, I am not eating my oatmeal as much. I'm thinking that this is not helping my quest for fitness. A girl cannot live on tofu alone (even though it would be nice.)