Ever since I did the calderdale leg 1 I haven't been feeling right (maybe thats what fellrunning does for you..!) My strength is ok because I did a hill rep session last week and it was hard- but I didn't feel I was not running 'properly'.

Over a longer distance though my lungs and legs feel tight and weak.
I was running better than I had done for a long time before this happened.
Has anyone else experienced this?
Is it over training? I was training constantly up to this point, but not really overdoing it.
For around a month now I have rested-taken it quite easy.