Hello Mochi -
Welcome to Susans. I am very sorry about your struggles.
In my old life, through work I have met many LDS members and I have spent a lot of time in Salt Lake City. I am no expert by any means but given my situation I did some research on the question of LDS stand on Transgender.
I made a lot of friend in the LDS community and I am worried how they would perceive my change (MTF) since I do value their friendship a lot. I have not come out to them yet, but I do see that at least one of them has been posting about gay and transgender church members every now and then.
While there is still a long way to go for full acceptance, overall LDS has opened up about gay and lesbians quite bit and they also openly discuss transgender. Every ward, bishop and families is different and your situation may be a whole lot more complicated. And while I do have many Mormon friends, there is still a lot which concerns me about the church doctrine and their standing on several issues.
I do have a few links for you I found during my research which may help:
Mormon Stories (not an official church site) - in this episode Transgender church members share their experience
http://www.mormonstories.org/mormon-transgender-experiences/Affirmation - Mormon families and friends (there are also links to facebook support groups for trans Mormons)
https://affirmation.organd then the official church site (unfortunately not covering much trans* issues)
https://mormonandgay.lds.orgGiven your special situation, at some point you may have to make a very hard decision and break with the church. I truly hope you can work out something which allows you family to accept the new you.
My recommendation would be to find a non LDS Therapist as a first step.
Fell free to reach out via PM if you want.
Hugs -
Sarah