I had to give up running as well after 20 years, early hip arthritis due to congenital defect in hip joint (FAI). Very very depressing, not to mention painful. Here's what helped:
- get outside as much as possible, in nature, not city.
Even walking helps mood. Studies show walking in
nature (not city streets) lowers cortisol
and improves immune system.
- running provides some people with lifestyle structure,
which is lost when you stop, so try to rebuild some
structure via hobbies, clubs etc.
- huge loss of endorphins/hormone changes when you stop
running, so try to get out there doing some high
intensity stuff. Biking is somewhat painful for me,
but helps. Strength training (e.g. 5X5 stronglifts)
has similar endorphins/growth to running because you
can feel yourself improve every week, that's helped a lot.
- if lifting weights, be sure to have perfect form,
I tore my rotator cuff due to poor form on BP and
overhead press.
I've had brief contact with running friends, i've distanced myself because i don't want their pity, and let's face it,
injuries are boring and bad karma for most other runners.
Still not sure what to do on that front. Have volunteered for some races and when people ask why i'm not racing, my reply is a terse "giving it a break for now",
but i always feel good after volunteering.
Biggest loss for me is not racing or going for PB/SB. Bike racing is too hard if you're new to it. I just focus on small goals, timing myself on sections of a route/climb etc.
Enjoy sleeping in sunday instead of waking up early for long runs. Pamper yourself a bit. Read about the 5 stages of loss/love, you must spend time in each stage before full acceptance. You will bounce back and forth for awhile, but it seems to get better with time and reflection.
Better to have run and stopped, then not to have run at all, i've got a lot of great memories. And let's face it, we all stop running at some point, except for the "lucky" ones who die while out on run!