How do I come to terms with who my military service made me?

You went where most people never go and saw what they cannot picture. It changed you. That is not damage to be ashamed of. It is the natural result of carrying real weight. First, let yourself say plainly that you are different now, and that the difference has a cause. Some of what service made you is hard. Some of it is strength. You learned to stay calm, to act under pressure, to value things others take for granted. Do not throw all of it out because parts of it hurt. Sort it slowly. Keep what serves you. Set down what does not. Reckoning is not a thing you finish in a weekend. It is a long, honest conversation with yourself, and it goes better with company. Find one person you trust and start talking. You are not trying to become who you were before. You are deciding who you are now, on your own terms.