Hey, I think everyone has vented their frustration and depression on here, and the support is what this place is for.
I know from various points in my own life that feeling when everything you've worked for crashes down. It leads to a huge depression and in my case and probably a lot of other peoples a huge surge in GID, and it sounds like you are in the same place. My advice is that you need to talk about your life and career as well as your GID with your therapist. The mood swings are part of been depressed, and feeling constrained, your also probably looking forward to starting therapy for GID, so you will get excited and then feel powerless while you are waiting; that's what's happened to me. Once you start moving along the care pathways it calms down, that is until something new is dangled in front of you!
The main problem is getting out of the downward spiral of your depression. I was told to be brutally honest with myself, so I could understand myself, and then understand why I kept perpetuating it. When you understand the cause you can start on a plan to improve your life.
The plan should be honest and achievable, and be filled with small steps that build to the overall goal, and provide milestones that you can be proud to have achieved; this will give you positive reinforcement and you can start building yourself up and regaining confidence. For example you say you're tired of been overweight, it might seem pointless but a small walk every night, which may eventually lead up to running (you'll want to lose weight for HRT anyway). Regarding jobs, find ANY job, seriously it will improve your self-esteem, especially in comparison to been unemployed. Also getting a better job is much easier when employed.
Consider what you actually enjoy doing, what strengths you have, and try things, it may take a few different jobs to actually find something (it did me) but each time should help narrow the search to what you really want.
Finally it is going to be alright, it never seems it when you are down in the pits, but it will be alright! Remember small steps!