Waking every 2 hours

[Desertress]

MY 9mth old ds has always been a really good sleeper and started sleeping throught at about 10 wks. That was up until a bout a month ago..... now he wakes up every 2 hours and its driving me insane..... he wakes up has a short BF and then goes back to sleep again.... if i leave him to try and settle in his cot he just starts screaming and then takes hours to go back to sleep.

Anyone have anyidea on this one as i cant handle the broken sleep anymore, it is makeing me very moody and irratiable.