It happens man. Sometimes I find that if I train too much, I seem to actually regress. If I take some time off (a week or two) I actually seem to improve. I have no idea why that works, but it does for me. Maybe I'm over thinking stuff instead of just letting it flow. I don't know.
Have a couple beers and relax. There's always tomorrow.
Happens to me as well. When ever I hit a road block in my training where I feel like I'm not getting any better I get way too frustrated and do stupid things. I always seem to come back way better when I take a little while off, for me it's a week. When I come back I feel like everything has solidified.