I have the roommate from hell. I took over the lease when her last roommate bailed. My name isn't even on the lease, I just initaled over where the last person had written.
I am moving out. I was told I needed to give 20 days notice from the end of the rental period. So I have to wait two weeks to turn in my notice?? Plus my roommate is shooting down every potential replacement for me. Her excuse will be oh she's ugly, or I want to live with a guy. Is that even legal? How many people must I find for her to shoot down before it is no longer my problem?

Is the landlord aware that you moved in as a replacement for the old tenant? Do they have a copy of the lease with your initials or your signature on it? Who told you that you need to give 20 days notice- was this the landlord or the roommate? Does it say anything about this in the lease? The 20 days notice part probably means that if you choose not to continue your lease for another year, you must give at least 20 days notice before the lease ends. This might not apply to you, since you are a subleaser.

If you are not on the lease and did not sign anything, then technically your roommate is solely responsible for the rent and you would be free to move out whenever you want without even having to find a replacement for yourself or giving notice. However, that might mean that the person you replaced could still be held responsible (since they are on the original lease), so it could create a mess for them if you leave.

A lot of this really depends on the paper you initialed and whether that is considered official.