I was having the same problem, so I made sure I got out of the house each day. Went to the library, went to the shopping centre (even if I was only buying one thing) made an effort to go to meetups on a couple of baby forums and I have found a new friend that lives only a suburb away from me. We had coffee yesterday!
I am also going to start going to a class (maybe kickboxing!) which will help me get fit, get me away from Tia (as bad as that sounds ) and give DF some time with her.
I know it's hard, but you just need to make the effort. ( And I do have days where I sit in my daggies all day at home )