For almost the past week my 7 month old daughter has been waking every 1/2 hour or hour crying. We co-sleep in our bed and we also attached the crib as a sidecar and sometimes she sleeps in that. It doesn't seem to matter where she is sleeping, she still wakes up crying. She has two bottom teeth and so I thought it could be teething pain. I have tried giving her homeopathic teething tablets and/or tylenol. These things have seemed to work in the past but haven't made much difference this last week. When she wakes up crying I either cuddle her back to sleep and then roll away or I nurse. She usually goes back to sleep pretty easily but still wakes up crying within the next hour. This goes on for about the 3-5 hours (from 8pm to about 11pm or 12am, last night 1am) then she sleeps better for the rest of the night, still waking every couple of hours but not crying. She seems to be healthy and happy during the day and has been taking pretty decent naps. Yesterday she napped for 2 1/2 hours in our bed (longer than usual) One more thing, we just got back from a week long trip to Baja where she slept with us in hotel beds very well.
What could be causing the waking up crying?
What can I do about it?
When will she start sleeping longer stretches (longer than 2 hours)?
Is our current sleeping arrangement causing her waking since she seems to sleep better for naps when I am not in the room? I don't think I would be able to put her to sleep in another room!
Sorry for the long post and thanks for any support/advice.

-Another sleep deprived mom