Omg, I feel for you, man.
I always hate to be such a downer on the holidays. but it really does suck how everyone else can be laughing and having a good time and I'm unhappy or uncomfortable. and worse, I feel like the only one.
I pretty much hung out in my room to avoid people all day today.
Luckily, though, my accepting family far outnumbers my unaccepting family.
If this is the same for you, or even if you have one strong ally family member, maybe you could get them to talk to your sister? Maybe she won't listen to you, or care about her relationship with you, but if she hears it from someone else, she might listen. She (might not) be making those jokes if she thought people (besides you) were going to call her out on them.