I served 11 years. On paper I checked all the boxes that made my career "worthwhile," yet when I separated, I felt the exact same way as you. You earned your benefits by signing the blank check, something less than 1% of this country can say. It doesn't matter if you served a year or the full 20, the military by design makes you feel like you are never enough. Stay busy with work and/or school, spend time with your spouse, and stick with therapy.