Seems simple to me. You are a speed based 800/1500 guy and you've been training to run 8K and 10K cross-country. You are struggling to keep up with the distance oriented teammates and as a result you are tired all the time. It is affecting everything in your life.
Don't be so obsessed with keeping up with them. Go slower on all recovery days. Don't work so hard on the long interval days. Concentrate your mental efforts on the shorter interval days.
My experience is a little different. I was a better XC runner than track runner in high school. But then I sucked at college XC, and it took me years to realize it was because my best event was about 3000m. I would get beaten badly by teammates in XC and then I would dominate them indoors. I had teammates who were two minutes ahead of me in XC that I could beat by 30 seconds in the steeple.
I should also say that I have seen a lot of collegiate runners suck in their first year, and to then improve a lot sometime their sophomore year as they learn to adjust to everything.
Running is a crazy sport. You work your ass off for 365 days a year, and at least half of those suck. All to have 3 or 4 moments a year where it all comes together and makes all the sacrifice worthwhile.
You are fast, no doubt. But listen to your body and slow it down a bit. But have confidence you are going to kick it come track season.