You need to have a well-balanced diet (WW is a great program that teaches healthy habits).
If you are spending time with Thor, take him on a stroll...even if it is for 10 minutes. Getting you BOTH out of the house is good and you are getting some cardio and strength training in by pushing the stroller. Over time, just build up your pace if you can. At work, walk on your lunch break. I get an hour lunch, so I walk 30 minutes and pump/eat the other 30 minutes. When I get home, I take care of what I need to and give Lilyan attention, then I lift weights while she hangs out (yesterday she watched me some and even smiled at me). It takes about 10-15 minutes for weights. Its nothing hard core, but I am trying to tone and just do what I can for now.
I realize its hard and I can imagine with going to school on top of it all. Oh, you could park your car far from the building and walk. Just some suggestions...I know its tough! I wish I had more time to jog, but I really only get a chance on the weekends until we get in a better routine.