Now that sounds familiar! I had the same thing with DD - she was a beautiful sleeper and then a monster baby took over my DD at about the 5.5 month mark. It did pass but I'm sorry to say its back again at 9 months. I think its just one of those things you have to expect in the first couple of years. I've been told that when your baby is going through big developmental changes you can expect bad sleeping, and about six months is definitely a big time for change.

All I can suggest is what I did to get through - accept that you can't change it and that you will be giving lots of cuddles until this stage passes. You might need a few cuddles yourself by the time you're done