Running kind of sucks!!

So, I just realized that Running on a treadmill verses running outside or on a track, is SO different and a lot harder too! I feel like on a treadmill, I can go and go, and not get nearly as fatigued as when I'm just running outside! I should have figured it out since the treadmill is kind of helping you along the way!! Dumb Me! It just makes me not like running as much anymore when I'm not on a treadmill! I just don't feel like I've progressed any with my endurance. I just need to MAKE myself run more outside, cause I seriously leave that hanging compared to my swimming and biking (which I absolutley love now!) The Running is only a 5k, but still, I need to be better with it!!!