In many cases being a single parrent was actually easier - no one else to look after apart from children and myself, being able to structure my day purely around myself and the kids, no one to have draining arguments with etc.
That aside, the stuff below is what I did:
-Get up early, regardless of when baby wakes up - if she was awake I sorted her out, if not I had time to complete some househod tasks/ exercise.
-Do most household tasks with baby awake and just take her with me and talk to her. I have fond memories of times she lay on an improvised mattress while I was hanging up the washing next to her, showing her the clothes and just rambling on about stuff.
-Get out of the house and walk somewhere every day for an hour, come rain or shine. It really helps improve your mood to be exposed to daylight (however little) and the extra exercise helps your mood and weightloss. If you do it at the same time every day baby might even get used to sleeping regulary.
-Remember the first year or so will be the hardest on you, physically and emotionally. It really does take that long to balance your hormones, get used to another little person in your life, to stop fretting so much and to allow baby to develop a regular rhythm - be that sleep, poop, hunger, be active or whatever.