Hi,

It can be really hard going when their routine changes so radically for no particular reason. Usually, there is a reason, just not one that it obvious to us, at the time. Tell us about what his previous sleep pattern was like? Do you generally co-sleep, or is this just in response to his frequent waking? What are daytime sleeps like now? How are his eating patterns going? Is he much of an eater?
If you have another bed in the house, for a night or so you could leave him in bed with his dad and go get some sleep so you are well rested enough to make a plan. It's not as silly as it sounds. There are some good books around like Elizabeth Pantley's "No cry Sleep Solution"
Regards
Barb