I think this is a common age for babies to start waking more often. They are getting ready for a lot of exciting milestones at this age and that seems to lead to more night wakings. Also many mums that their babies wake more often at night when they go back to work. It seems to be that some babies try to make up time with their mums at night. It's kind of cute unless you're the poor tired mum who needs sleep more than ever having just started back at work. From experience as a working mum who ended up with a baby who's sleeping went totally out the window, it does eventually pass. What I can't tell you as I was living in a sleep deprived blur, is how we coped in the meantime. My best advice is to put out the call for help, accept all offers, and be kind to yourself, rest when you can.