Sorry you having to go through this, having been there I know just how impossible itvall seems having to say goodbye to someone you truly care about.
I would sigguest writing maybe a list or a letter of all you want to say, because having regrets about the unsaid is really torturous, and in the moment fir me at least I found saying the right words too hard.
If you are going to be seeing a new T then I recommend using them for continued support.
After that it's just take life day by day, im a couple of months on now, I still miss her and I'm still sad etc, but day to day it does get a little easier, and ok the days it isn't, then just allow yourself to feel all that you feel, mine is sadness, hurt but also anger.