Bed time

The past week bed time is a struggle. E is nearly 13mth old and is still have 2 naps no bother. She self settles well both naps. 1st nap is any where 1.5 -2 hour second is 1-1.5. Up from last nap around 15:00. Bed time starts at 18:30 in bed for 19:00. In the past she used to maybe roll about for 5- 10 mins and go to sleep. This past few days she lies downs but it kinda looks like she gets upset because she doesnt fall asleep and doesn't know what to do. I have to go in a rock her to sleep, something I've never done and she always asleep by 20:00. It's very warm here at present and she is showing a lot of teething signs. The way she is acting makes me think that she may be having to much day sleep and shes tried but not quite tried enough to fall straight to sleep. Any advice?? I really dont mind spending the extra time with her but sleep is a big time anxiety trigger for me and I can feel myself beging to spin out that bedtimes arengoing to be this upsetting for ever!!