Yes, it is normal to be depressed when injured. Second, you've never really had a chance to absorb a lot of the things that happened this year. You had a great season and it kept you busy. You had some down time but you were still on the high from your season. Now all of a sudden you have some time on your hands, you can't do what you want and there's a lot of opportunity for things to sneak up on you. You had a fantastic year, but you also had a tough year full of sacrifice and significant loss.
It's OK to be sad. Yes, a lot of it is related to the injury, maybe all of it. But maybe some of it is related to other things and your life. Take a moment to reflect. Let the emotions come as they will. Maybe now is the time for you to absorb all that's happened this year.
Your knee will get better and so will you. Just give yourself the space to process all of this stuff.
I'm thinking about you.
Now I'm off to your injury thread to answer some questions there.
Living life like there's no tomorrow.
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2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS