Advice on separating early

Read the rules and I don't think this goes against any of them.

I really want out. I've been active duty for about 3.5 years at this point and I have 2.5 more to go if I were to fulfill the rest of my contract. This job has taken such a severe toll on my mental well-being. I used to enjoy what I do but now I literally dread every second I'm at work. I'm so unbelievably burnt out and every day I spend still in the military feels like a day I'm wasting of my life. I could go on with specifics about all the personal reasons I want out but for the sake of simplicity let's just say it's for my mental health. No, this isn't just "I had one bad day at work and I'm crying about it here and I wanna go home". This has been going on for almost a year now and it gets worse every day. I keep telling myself it'll get better and it never does. A lot of the things that are causing me so much anxiety and stress can only be fixed outside of the military even with all the resources the military offers. Again, this isn't some rash decision; I've spent countless hours really thinking about it and I know that I want to be done. I don't want to waste the next 2.5 years of my life killing time trapped in a job that makes me miserable.

I feel lost. I know I could pop on a drug test and that's (to my knowledge) a surefire way to get separated, but I don't know how that'll affect the rest of my life outside the military (i.e., type of discharge I'd get, how it'll affect future employment with places that do background checks, how it'll affect any benefits I'm entitled to, etc.). If it's relevant at all I work in aviation/squadron and I plan on continuing that line of work just as a civilian, and I don't want to screw that up. I'm getting an initial mental health evaluation in a couple weeks to hopefully get referred to a therapist. I'm not sure how common, reliable, or fast a discharge for anxiety/depression is or how to even go about that process.

Any information at all is helpful. I'm getting desperate to make something happen, because I'm realizing nothing is going to get better by just waiting.