AIW for not lending my sister money even though I have some?

My sister asked to borrow $2,000 because she is behind on rent. I have enough savings, but she still has not paid back the money she borrowed from me before. She called me selfish because I went on vacation. I told her my savings are for my own needs, not every time she runs out of money.

Now my family says I should help because she might lose her apartment. Am I wrong for saying no?