I am so sorry to hear about everything that's going on! You know what they say, when it rains it pours.... but I hope everything can clear itself up for you!
That said, I really hate saying this and be negative but DO NOT DISREGARD THE LETTER! While it does seem HIGHLY suspicious that does NOT mean it's fake. I had horrible roommates also one year and they reported to management all complaints they could think of and the only notice I did actually receive WAS NOT SIGNED and did not have everything filled out to make it official.

But it was official, not just a scam. Now this was a rather large college complex and I don't know if your complex is a lazy and stupid as mine was.... And actually I only had a few more months left on my lease too....
But like everyone else said DO NOT trust your roommate! Another idea: what's your boyfriend's living arrangement. Could you and Prada spend the next few months with him?
Thinking good thoughts for you!
-Vicky & Zoë
P.S. My Dad's a real estate attorney, so I'm familiar with leases/contracts and what not. Don't forget that as much of an a'hole your roommate may be, a *known* violation of your lease, such as having a pet, could wind up with a
HUGE fine (most places charge something like $200 a day that the dog isn't gone) and you getting
evicted (and then that's on your rental history).

Just be careful of the situation!