Too much too young(soon)

18K run tonight did not go to plan. I was OK fluid and energy wise but I was very stiff at the start and the first few km's were painful. I dropped 5k in 26 minutes and 10K in 59 so much slower than yesterday. My foot began to hurt badly around the 10K mark and I had to effectively stop running at the 15K mark and walk-run the rest. I finished around the 1:51 mark but last few km's were walk/jogged. Same sore point as before but this time much more intense and pain coming over the top and down to my big toe....not good. I'm going to change my trainers as this resolved it a bit before and I must be near the 500K mark with those ones now.......nice video link to the Specials there..seems a long long time ago "Chained to the cooker cooking current buns"