This is really long, sorry.
Sounds like you have 2 things going on.
First her naps schedule is changing. She is probably about to hit a major milestone and a growing spurt. Look at how you schedule her first part of the day. What time does she wake up? Maybe you could encourage her to get up earlier. Feed her breakfast early.
Make sure she is super active physically. Go the park, or play in the back yard. Get her a trike with peddles. Have her drive up and down the sidewalk while you jog or walk. Get her a bigger slide, have her practice hopping, skipping. Play Simon says. Feed her a hearty lunch. Then start doing some quiet activities. Let her color or play inside with no loud noises, Play quiet music. For nap time, make sure her room is dark.. I used to put up quilts so that I could block out the light. Read a story to her. Do not engage her during this time. Read slower and slower. See if you can get her to just do a 1 1/2 hr nap at the most. When she wakes up give her a small snack. and again get her outside. Keep her active until dinner. Then stay on the same night schedule. My mom suggested this technique to us and it worked great. I always remind parents that the length of time you rile up a child is the same amount of time it will take to calm them down. Adults can stop playing instantly, but a child cannot calm down the same way. Try bath time right before bed, close the bathroom door, play quiet music, bathe her in very warm water, do not excite your daughter. While bathing her, rub her with stronger rubs, almost like a massage, speak in low tones. Wrap her in a towel take her to her bedroom. Make sure the lights are low. Have soft music or a white noise machine playing, dry her off with strong wipes, like a massage. Put her in her pajamas.
She will be so tired and calm, she should be pretty sleepy by this time. If you can turn the heat up a few degrees, the warmth will also help her fall asleep.
If you look through Mamasource you will notice many, many posts about this. Your child is not alone..
The second thing is she is having bad dreams. There was post on Jan 26th, 2009 This was my response. She must be a very creative and intelligent child to scare herself.
You need "dream coins". A client told me about these many years ago. They are "magic coins". They look like quarters to everybody else, but when placed under your daughters pillow, all scary things go away. Also when you travel, the quarters are great, because you do not have to worry about not having one, they will work on out of town scary nights, just like at home.
This worked very well for our daughter. One time when we were changing her sheets, I found a lot of coins under her pillow, I asked "why are there all of these coins under your pillow?". She said" I was having a really, really , scary dream so I put lots of coins there to make them go away"...
I remember another mom responded to this on mamasource, she said to get a spray bottle and to pour water in it, then you use this to "spray away" all of the monsters all around the room, closet, wherever the scary things are... I loved the idea...