Night Time Terror

So for about a week now Abbey has been having troubles going to bed. First it started out that it was too dark in the room. It has progressed to her now crying before bedtime and us buying two bright nightlights for each side of their beds along with the other two nightlights. That is right everyone, we have 4 nightlights in their room. We also are keeping the shades tilted so the natural light comes in. So for Abbey this has been working somewhat. She still cries and gets a bit panicked before bedtime however Ashley now cannot fall asleep. She has been staying awake in her bed. Last night I think she finally fell asleep around 9:30 (they are in bed at 8:00). She will come out a few times and check in with us but she usually is just laying in her bed. We have caught her out playing in her room. Last night she wanted her bright nightlight shut off and I think that is what finally helped her because now it is too bright for her.
So besides the initial fear of going to bed and all of the shadows....Abbey has joined us in bed everynight. Not just once....sometimes it is 3-4 times! Mind you this is not conducive for mommy and daddy to get a good night sleep. Last night Abbey also woke up just crying but couldn't tell Shannon what was wrong. She was out of it.
I was up working last night and Shannon had gone in to check the girls before he went to bed. He had checked on them before he had come down to kiss me goodnight and then went back up there and all I heard was "Abbey????Abbey???Where are you?" So that is enough to send any parent in a panic. Guess where she was....in our bed. She walked out to our room, climbed into our bed and was sleeping in my spot. That was just the start of the multiple trips into our room. I finally gave up on her sleeping with me last night out of pure exhaustion. I slept in the middle of the bed/mostly on Shannon's side and he slept with his head off the side of the bed. Abbey had half of the bed to herself!
We try talking to her and reassuring her that there are no monstors. We have light for her to see. We are getting very frustrated. We told her no more getting out of bed and sleeping with us. HELP!!!!