Hello, I'm new and trying to get the hang of all this...

Well I'm new to this whole thing, I've never really felt the need to diet because I was always thin, but about 2 months ago I had a beautiful little girl...and I gained about 30 pounds with my pregnancy. Well..after I had her, I dropped to 140 and I've just stayed there....my pre-pregnancy weight was anywhere between 115-125. I miss my old jeans! But here's the catch 22...my husband, daughter and I live with my husband's sister and her son....and they are ALL extremely picky eaters! I like cabbage, squash, steamed broccoli and things of that sort and they won't even touch it. So it's pretty much eat what's prepared. No complaining...or else the warden ( my sister-in-law ) will bite the head off of the person who is rebelling.  I pretty much eat when I can....try to get some sleep considering I'm up in the middle of the night changing diapers, making bottles, burping and all that great stuff. Anyone who is willing to give me a little advice on how I can start losing my gut...please...feel free to talk to me!

Thanks!