Fighting Sleep for 7 Hour and Counting...

From IndyMoms.com

Help! Lolli will NOT sleep. She is miserable and screaming no matter what we do. A few times we have gotten her quieted but as soon as she starts to drift off, she screams and wakes herself up. She and I went to the mall today for a few hours and apparently that got her all out of whack. She hasn't really been able to sleep since we got home. She just cries.
She isn't hungry (she just calmed down to eat for about 10 minutes), she isn't dirty (we tried a bath to calm her earlier), she isn't constipated (just pooped) and doesn't have a fever. She isn't acting like she's in pain (except for the crying, of course). She is just way too tired.
The 5 S's are NOT working, no matter how long we try. She isn't liking her swing right now. She'll sometimes quiet for a minute when we're holding her but then screams again. The only thing she consistently likes is when we swing her car seat around. My back is spasming and DH can't do it much longer, either. We tried a car ride and it worked, off and on. But that was with us pulling over every few minutes to swing her car seat.
We are so sad for her and it's breaking our hearts not being able to make her feel better. This is by far the longest time she's ever acted this way in a row (previous "record" was 4-5 hours). How can we get Lolli to fall asleep and stay asleep, at least long enough for her to wake up rested enough to sleep some more???