D.M.
S.,
Totally normal sleep pattern change...this will happen over and overa again. Last week my 30 month old had one, and he was waking at 5am to tell me he was done sleeping and it was time to get up...
My son at around this time went through a transition and ended up with only two naps of two hours long, and went to bed at around 7:30pm. It's just a matter of making the transition smooth and having patience.
This is roughly what my son's routine was like...
6:30am wake and bottle
7am 'breakfast'
9:30am nap (2 hours...usually, pending no teething or other issues)
11:30pm wake and bottle/meal 30-60 minutes later once he was one solids regularly
2:30pm nap
4:30pm wake and bottle offered
5:30pm dinner
7:30pm Bedtime...
One or two wakings for bottle or diaper change...
Now, for the most part before solids I fed on demand...and I read a ton of books for help with adjusting my son (never a good sleeper) to getting large chunks of sleep. But, once he was on the solids regularly and we had a good routine going, he would sleep at night for 6-7 hour chunks at a time.
Getting too much sleep during the day can effect how we sleep at night or what time we wake to start our day. I know if I nap when my son naps during the day, I wake much earlier than if I don't. And, then my whole week is thrown off because I'm dying for a nap midday at work.
For my son I have stuck with a 3 hour on/off time frame and that has worked pretty well for him...of course now that he's older it's not the same, but it's worth a shot.
This is also a huge transition time, sleep, growth and becoming more and more aware of her surroundings is going to effect sleep. Just take care to make the transition slowly, and keep in mind that it WILL change again in a few months.
Good Luck!