Is it horrible if I leave early?

Basically what I’m asking. I’m here as a short term summer au pair, and the children have been an absolute nightmare. Constantly screaming and throwing fits all day long and yelling at the parents and myself. They are so rude and disrespectful that I am in tears nearly every day. I have 2 weeks left of my contract, and I am wondering if it is unheard of to leave early