Just saw your thread for the first time today. Congratulations on a lot of growth this season. You probably can't see it now because you are stuck with the disappointment of your last performances, but your training clearly shows great gains in fitness that will stay with you to the spring and into senior year.
Consider your progression in the recurring 4xmile (3 min rest) workout and your stagnation in the races that follow:
8/9
6:20, 6:21, 6:27, 6:30, 6:24
19:48; 6:17, 6:25, 6:20
9/8
6:22, 6:32, 6:30, 6:27, 6:28, 6:23
18:43; 5:34, 5:56, 6:10* (either your best race by far or a true 5k and your 3rd mile is closer to 6:30)
9/22
6:06, 6:12, 6:12, 6:18
18:42; 5:44, 6:03, 6:17
10/10
5:51, 5:46, 5:50, 5:58
19:00; 5:25, 6:25, 6:30
10/27
5:55, 5:45, 5:45, 5:43
19:00; ?
I'd be interested to hear your splits from the state meet. Was it another 5:20-5:30 opener?
For reference, our 19:05 performer ran 5:49, 6:11, 6:18, and I thought his open was a little aggressive.
He never ran anything as fast as the workouts you were running.
We had an athlete who was in a situation similar to yours it sounds like. Trained like our #2 all year and started out fit and fast. Her workouts got stronger through the year but with only minimal gains in race performance. By season's end, she was getting beat significantly in the second half of races by girls she would run into the ground during the week. Part of her issue was going out too fast, not even just the first mile of races but the first half mile. Another girl on the team might come through the mile with her but she would have run the first half mile 10 seconds faster--an eternity over 800m.
At what point did your #5/#6 guys catch you and pass you?
The best thing you could do would be to have a conversation with your coach and ask him what he saw from you. Why were you not racing faster as you were getting more fit? Were you not recovering from workouts? Was something off about your stride, maybe an injury? Were you going out way too fast and sabotaging your races in the early going?
Incidentally, our female athlete I mentioned did the same thing every race last fall but came out and had a great track season. I'm hoping to see the same transformation this year. If it's something as simple as not having figured out cross-country racing, you'll still have a lot of aerobic gains to carry over to the oval in the spring.