I would also suggest that you get some Mylicon & Teething Tablets (they're all natural) to keep on hand. They worked wonders for our DD at that age. She slept up to 11 horus a night until she was 7 months old and then she too would wake up screaming & crying. We didn't realize until a month later that it was her bottom 2 teeth coming in. After that, we bought Hyland's Teething Tablets and gave them to her the minute she woke up crying. Within minutes, she was relaxed and going back to sleep.
She also started to get ear infections around that time so it could be any of the three things: gas, teething or an ear infection. I guess I would try the Teething Tablets first, then the Mylicon and then if those don't work, think about getting her to the pedi to check for an EI.
Glad the last few nights have been better.