did you take a break in between seasons to rest?
are you used to two practices a day or did you just jump into it?
have you checked your iron levels? are you getting enough calories and nutrients?
are you sleeping enough?
i suspect either you did not rest after outdoor track and beginning your summer training or you have not doubled before. sorry if my assumptions are wrong. either way you should take some downtime to rest especially as it sounds you are both physically and mentally tired. don't be afraid to step away from training for a little bit as the best training comes from when you are actually enjoying what you're doing and have the motivation to preform day in and day out. a counselor at a camp i went to (who runs at stanford) told me to run hard and rest harder. runners, including myself, know how to push themselves but have trouble taking it easy.
here's my story: after a great summer of training and early season workouts i plateaued in my performances and then tanked. i was devastated and considered giving up running because i would pour myself out in track everyday and then never saw the hard work pay off in races. i got up in the morning and aqua jogged or lifted or cross trained after practices that i didn't jog in the mornings. i figured i could outwork anyone. but truth be told i ran myself in the ground and made running a chore over enjoyment. after the end of cross country i waited a week and then went for a run. no endorphins, no running high despite feeling fine physically. i mentally did not enjoy it. i waited another week and gave it another try knowing if i didn't enjoy it anymore i may just focus on something i found enjoyable. boom. i felt fast, smooth, and i probably turned the run into a tempo run but i felt so good and wanted to go fast. i was back. i trained myself until january with the permission of my coach before returning to official practices for indoor. i started busting out workouts i had never done so before and had a major breakthrough. i was scheduled to run the mile at a meet which was cancelled so my coach had me run a solo time trial. boom, 2 second PR with strong winds off of base training. keep in mind i did not improve the past two years in the mile, i ran the same season bests. took 9 seconds off of my 1000m opening race to last race which was a 7 second PR. during outdoor i took 10 seconds off of my mile. i was basically running like i had never done so before.
during this time i doubled my iron supplementation. so to sum it up: take a step back and take the time to find the enjoyment in the sport again, review your training to see if you're over training (i.e. you jumped into doubles without building up to them), check for any deficiencies, and take care of yourself with sleep, nutrition, stretching/foam rolling/icing