I used to train 5-6 days a week in high school. I didn't do any cardio, but I did train using workouts arnold did. Talk about overtraining like a mofo. I didn't get sick very often or feel bad, but I could not gain for like a year until I started reading Arhtur Jone's and Mike Mentzer's stuff. Then I went overboard with that and realized you can undertrain. Now I'm training 4 days a week each bodypart once a week, but some over lap on the chest, delts and triceps.
Off days are great. You have to get it into your head that that is when you recover and GROW.
Now that I think about it I was "kinda" like you Jkurz1 in high school as far as over training although I didn't watch my diet much except eat alot.
You should take like 2 weeks off from any lifting and cardio and sleep 10 hours every day, then hit up your weights and take it easy on the cardio compared to the intensity, frequency and amount you do now.