HI there - what Sarah is saying is true - I think you are in the midst of the switch (i'm there with you!). If you shorten the first nap, put to bed a little earlier for the pm nap as they can't last as long as before. then it kind of evens out the day. if you are worried then about too much pm sleep, you can always wake her by a certain time so she goes down for bed at a preset time.
I'm also going to pop this over to the toddler sleep forum, so you may get some more age appropriate advice from some seasoned switchers! (at 12months, we consider them toddlers here