Does each race in Starcraft 2 Share The Same MMR

I have been playing Starcraft 2 with Zerg mainly, I reached my 1000 wins with zerg and now I am starting out with Terran.

Will my MMR transfer to Terran as I am a master league Zerg player? I have been practicing off the ladder with Terran but I know I will most definitly get wiped off the ladder when I start because of my former Zerg MMR.

Do I have to lose a ton to bring it down?

MMR is not based off of race. A lot of people have been asking Blizzard to introduce MMR decay for races that you don't play. Basically every forum post gets bumped who ask for this feature.

Any MMR changes will be listed in the patch notes, so if a new patch is released you'll find your new information there.