M.M.
Hi C.!
I don't have a magic answer to your problem, but I wanted to share some insight from my own experience as a mom.
When my dd was almost 8 months old, her sleep patterns became horrible. She was waking up all the time (every 1.5 to 2 hours) and would vacillate from just babbling and laughing to crying/screaming. My husband and I were going crazy. She co-slept with us, by the way, and she still did all of this!!
I went online and posted my situation (this was on a different board). I got a ton of responses from other moms saying that 7/8 months is a time when many babies go through a rough sleep pattern - one even gave me a link to a great article. I tried to find the article for you, but I couldn't. If I do, I'll definitely send it to you.
The bottom line was this was normal behavior and it usually only lasted 2 to 6 weeks. My DD went back to her old sleep patterns after about 3 weeks of this.
The reasons given were that most babies at this age are going through three HUGE developmental milestones:
1. Physical Development - At this age, they can suddenly crawl or move themselves around, they can pull themselves up, etc. This not only excites them and causes them to want to practice all the time, it can also cause their muscles to ache at night.
2. Introduction of Solids - around this age, most babies began to take in a significant amount of their calories from solid foods. This not only can cause physical pain - such as constipation, gas, and so on - but it is also incredibly exciting and stimulating.
3. Cognitive Development - 8 months is a classic age for Separation Anxiety. This will pop up in various forms as she gets older, but 8 months is traditionally the first big hurdle. She has started to get the idea that she is a separate being and this is both exciting and terrifying.
So, my advice would be to first rule out any possible physical problem. Is it possible she's suffering from gas or constipation? Is it possible she could have an ear infection? Just to be safe, have her checked out - better safe than sorry.
If she's otherwise completely healthy and you don't want to try CIO (I never have, but I know a lot of people swear by it), try not to lie down with her or nurse her (unless you want to) as that could easily become a pattern that won't end.
Instead, bring a chair into her room and sit next to her - hold her hand or perhaps sing to her. Do something to let her know you're there. I sometimes would just hold my dd (not rock her, not nurse her, just hold her while I sat down) and let her CIO in my arms. For some reason, this worked really well with her, although she would cry very hard for a while.
Take turns with your husband and know that this may take a few weeks. Buy some strong coffee : )
Sorry I don't have an easy answer for you! But I hope this lets you know you're not alone and that you beautiful little girl is very normal!