Neverending sleep regression

Hi ladies!  I haven't been around in a while because I've been so busy with my two little girls, but a problem has developed, and I could really use some advice.
After dealing with terrible sleep problems with my first child, I have devoted myself to making sure DD#2 was a good sleeper.  Things were going pretty well- I could hold her until she was sleepy, then put her in her bed, and she'd put herself to sleep.  Sometimes she wouldn't settle in my arms, and I'd put her down and say "Just try to fall asleep; I know you can do it", and after maybe 30 seconds of protest crying she'd settle down and fall asleep.  This was a major victory for us.  Then my thyroid decided to get wacky, and I was too tired to get up to nurse her in the middle of the night, so we started partial bedsharing.  This was not a huge problem because I taught her to be a polite cosleeper, and she napped/started the night in her own bed without problems.  This continued for a while, until she was about 7 months old.  
Maybe it was the tooth that cut two times and retreated before finally cutting through to stay; maybe it was the normal 8 month sleep regression; maybe it was the start of separation anxiety, but she started refusing to fall asleep no matter how tired she obviously was.  If/when we finally got her to sleep, she'd wake after 30 minutes and refuse to go back to sleep.  She'd wake in the middle of the night and not settle back down for hours. This went on and on.  
I had a little hope last week that she was getting better, but this week has been awful.  Now nothing I do works- bouncing rocking singing humming nursing sitting holding putting her down patting shushing picking her up.  When I hold her she arches her back, cries, kicks out with her feet and pushes me away or claws me with her hands.  If I put her down she wails.  I have tried anticipating her sleep window, but it doesn't seem to exist these days.  Even if I do get her to sleep, she's awake again, crying from exhaustion, after 30 minutes.  My DH takes her for me in the evenings and puts her in the swing- that conks her out but only perpetuates her sleep issues.  I get so frustrated, she's so miserable, and DD#1 has no one-on-one time with me anymore.  I'm covered with bruises from her kicks.  I haven't slept well (i.e. only two quick wakings to nurse) or had time to talk with my DH in over eight weeks, and sometimes I feel like screaming!
Can anyone relate?  I would say I'm pulling my hair out, but the baby does that for me!  

[AnnieBrooke]

It sounds awful.  The only things I can think of to suggest, you have probably tried.  They are to talk to her pediatrician, as the arching of the back sounds like something physical (or it might be, anyway) -- kids arch when they are colicky, for example.  The other approach would be to get her a lot more exercise in the daytime, so she is frankly just pooped at night.  But the arching and clawing you really sounds like she is hurting, so I'd see the doc before assuming the problem would just be solved by exercise.

[chinesebones]

Hi, thanks for writing back.  I think you were right about her being physically uncomfortable.   I've had concerns about reflux her whole life, but my pediatrician says it's not bad enough to treat.  There is also the physical discomfort of teething, which really seems to bother her.  After I wrote this, I gave up wrestling with her and just nursed and nursed until she could get herself settled and sleepy, or, if that didn't work, gave up and tried again an hour later.  
She's trying to stand and walk, beginning to talk, growing teeth: there's so much going on in her brain I'm not surprised she can't sleep!  We're seeing her doctor next week, and I'll get her opinion. For the moment I've stopped worrying about "ruining" her ability to self-soothe and am just doing whatever it takes to help her sleep.  I keep telling her that we'll see her through this.  Thanks again!