Reading all these hardcore replies I just feel like a pu$$y for not pushing myself to that level but still having the nerve to say I overtrained.
I was always an average runner from middle school through junior year and decided that I wanted to be GOOD by the start of my senior year. So I trained harder than I ever had that summer, doubling my weekly mileage on the second week, and doubling that mileage by the third week.
I was able to get by because it was the summer and I had enough hours in the day to sleep 10+ hours, lift often, and run hard everyday while also being able to eat plenty of calories. It wasn't all good though, At the beginning of the summer, I had achilles tendonitis in both legs and ran through it until the symptoms strangely cleared up on its own. I was in the best shape of my life.
When cross country rolled around, I had solidified myself as the 2nd best runner on the team, surpassing guys who for the longest time were untouchable in terms of their spots on varsity.
The funny thing about overtraining is: by the time you realize you've done it, it is too late for you to do anything about it. Although I placed high in the 2 meets I got to race in all season, I didn't get to race either of them healthy.
I went to a physical therapist and he told me I had posterior tibial tendonitis and was at the risk of a stress fracture. That is when I finally backed off and stopped pushing through my runs. The rest of my senior year was painstaking as I didn't run anywhere near what I was capable of (even though I did PR in every distance race).
It was hard mentally, debated quitting running after high school. Took some self reflection but I slowly built back up and was smarter about my training and now I am runner on the collegiate cross country team.