Losing sleep

I should be sleeping instead of writing this. Hannah has always been a good sleeper until this past week. She's been sleeping through the night (10 hours) since she was three months old. For some reason though she's been waking up more during the night. She woke up three times on Tuesday night! She also doesn't want to go to bed at her normal bedtime (7:15). She hasn't wanted to take naps. I'm feeling more run down because I'm not used to this. I'm not sure why her sleeping patterns have changed. Some possible reasons could be that I recently introduced her to chicken, she might be teething, or maybe she's just not wanting to sleep as much.