Is your DH able to help out? Maybe you do one night when you get up and and he does the next.

You need to find out the cause of these recent night time wakings. Does the dummy fall out, the comfort toy get lost, too cold/hot etc? There are numerous books out there preaching all types of sleep techniques.

It does take a while to get into a routine and at the same time your bub will be finding his own sleep pattern.

Good luck both at night and back at work.