Teachers: Have you ever felt like being tired of your job?

I have been teaching primary ESL for 9 years and I absolutely love it. I like the opportunity to be creative and my kids are mostly of a very good behaviour. I've been always looking for some new ideas in teaching and I try to keep up to date with technology. It's just that recently I started having a feeling of tiredness that actually affects my teaching. I'm fine physically, it's just I feel bored and it's kind of getting worse. I don't understand this and I'm not sure what to do? I can't quit, I have my family to support. Any advice will be much appreciated.