hon, it's so hard isn't it? My DS went through a similar period at about the same time. He'd been sleeping through consistently from about 12 weeks, then at around 5.5months he started waking during the night, at first it was only once or twice, but as time went on it became more and more often. By the time he was 8 months I was getting up to him 7 or 8 times every night and each time I would rock him back to sleep. Like you I wondered about teething, solids etc, but nothing seemed to make any difference. Personally I think it is developmental as they learn to crawl and pull themselves up, but that doesn't help you does it. Hopefully things will improve soon for you.