Please reach out to a qualified psychologist / psychiatrist if you are feeling depressed or low.
Its important to get mental health back on track before transitioning; simply because HRT can cause a lot of mood swings, and so can surgery and the rest of the process. Transition takes a mental toll on people and it is important to create robust mental health before one dives into transitioning. Trust me - been there.
What helped me was meditation and conversations with near and dear ones who were willing to listen. Meditation, journaling and goal setting should be done on regular intervals and lifestyle needs to be healthy and disciplined. That should bring you back on track dear.
All the best - do the needful and you will get better.