The Bank is probably the legal owner of the property and they have a right to evict you.
You are probably lucky that you are able to do a short sale.
You may have to consult an Attorney, because I cannot give you legal advice, but,
If you go to the Buyer's Agent and ask them if you can rent-back the place for 60-90 days; you might be able to work something out.
Plan B, would be to find a house or a motel room that you can rent for 60-90 days.
Lately, the Banks have been providing "moving money" to occupants who will move out in a timly manner, and without doing any hard to the house. You'd have to ask the Bank about that.
Good luck and God bless
Can the buyer sue for performance? Yes. Anyone can sue for most any reason, but there are so many other listings that it would be easier for them to move on.