As PRB and others have said, the camaraderie, brotherhood is what I miss. And like others I found that civilians even those close to DoD have no values, ethics etc.
I am lucky as a couple of folks started me early in saving and investing, so not working has worked out for me, as long as I am busy...
Everyone has heard it before, plan early, prepare as best you can, have a plan A and B....
Get your medical records in order, the VA comp can help....
If nothing else go to school get your head straight, and assimilate to the new environment....
Also never forget there are brothers out there just like you and as some of the old jokes go, you can reach out, and like it was yesterday start the same conversation over again....stay connected, it will help with your transition.
Good luck, CSM-H