i need a new goal

i took over a week off from doing my 5K treadmill interval training because the trainer at the gym suggested i do so when i told her about my leg hurting. she suggested i do the bike machine or something similiar and to give my leg a rest and if it still hurt after that to have it checked out. well, saturday i did the interval training again. and again, i'm in alot of pain in both my leg and now my knee. so i've pretty much ruled out being able to run a 5K in the near future. i'm pretty dissappointed.

what i need is a new goal. my focus is on endurance. so what if i cant run the 5K. i know i can walk it, or even the 10K like i used to do in Germany but thats not good enough of a goal for me. obviously i cant do anything with speed. so what is left to work towards? suggestions anyone? ( and dont say losing X number of pounds..focus is endurance, not a number on a scale)