She won't sleep

Its driving me freakin' crazy. My daughter claim she "can't fall asleep" 95% of naps and 90% of bedtimes. She refuses to lay still and be quiet. I'm going crazy about it. She can sit in there talking and singing to herself for hours, if I let her. Its 10:30 here and she JUST fell asleep. Yeah and she woke up at 7:30 this morning. She only took about a two hour nap. This nap she took easily b/c we were on our way home from Wal-Mart and she conked out in the car. Thats the ONLY easy way she takes naps anymore.

Ever since we came went to Chicago, her sleep has been messed up. Yeah, a month and 1/2 ago. She had alot of late nights on that trip and alot of missed (or just falling asleep in the car) naps. It couldn't really be helped and she had a hard time falling asleep even when we were home at nap and bedtimes b/c it was a strange place. So, first it was bit rocky getting back to normal. I thought it was take a week maybe two weeks and she would go back to talking in her bed for about 20 minutes or so and then just fall asleep. It just keeps getting worse and worse. She has a set routine and I'm pretty sure she's really tired alot (dark circles, rubbing her eyes, wanting to cuddle alot, getting cranky more easily and even yawning) so I don't think I need to NOT let her nap. She seems waaay too young for that. BUT, I don't know what else to do so that naps and bedtime don't turn into hours long ordeals. I get sooo frustrated at her when its like that (and she at me). Anybody that might actually be reading this, if you have suggestions, I'm totally game.

S