Despair, 11.2mi @ 5:35/mi, full tilt

For all intensive purposes, excuse my language, I am totally and completely fucked. Today, after a day off, I go out and run and my breathing is so restricted that I quit my run at 11.2 miles because I was running pretty much balls to the wall. I just looked back on my log and I've done the latter 14miles of 22 mile long runs at a faster pace than I did this 11miles. That is atrocious. I am disheartened to say the least. My legs actually didn't feel too bad, but I was seriously breathing like I was running a 1500m race and by 8 miles my chest was actually aching. I wish I could stay positive but I am having a really hard time, things feel like they are unraveling in a big fuckin hurry. I can let a couple of bad workouts go but now I'm in full panic mode. I don't think I can handle any more mental beatings from here on out so I've decided(and this could change) that I am going to do a relaxed long run on Sunday, then do a gradual two week taper, problem is the last couple weeks have been shit anyway. Ugh. Well to end this on a semi positive note, my ipod earphones crapped out the other day and I picked up some new ones yesterday, and they kick pretty good.