You are definitely overtraining. Listen to your HS coach and do the workouts prescribed, but as one poster point out...train, don't strain. This is lost on most HS and college kids. The goal of a workout isn't to run yourself ragged or really feel like you just put yourself through a war. Let the races do that. Leave everything on the track in races (running smart of course). Workouts and especially easy days should just be building to that. Although I only ran 27 min for 8k in cross ( 50.9 400 and 1:56 800 guy) on some of my easy days I ran about as easy as you. So if you are only running 11min for 3200 I think it is safe to say you can slow down on easy days. If you feel like you are super relaxed and didn't run after your easy runs...that is a GOOD thing. On workouts don't feel like you have to kill everything. If you have an insatiable desire to feel spent, do your workout at pace and then do some strides of 100-150m running hard at the end or on easy days. Then kill it on race day. Good luck.