Going Crazy at home

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So...I'm going to try this to not sound like I'm complaining....I'm sorry if it comes off that way, if anything I'm mad at myself for feeling this way when we worked so hard to acheive this goal.

Basically we had been fighting with my fiancee's ex for 3 years to get more than just every other weekend with his kids, she has some issues that were concerning us, child welfare got involved, she just wasn't taking care of them, and she would run off with them on his weekends. In the end she had stopped paying the mortgage on the house he had let her keep so they both went bankrupt and she didn't have anywhere to live so the judge ruled it was better and more stable for the kids to be with us, she would still have full visitation (she has yet to contact the kids in over 2 months since this happened.)

So that's the background, I had to quit my job (which is in massage therapy so I lost clients) to be at home because my fiancee makes more money than me and has a steady paycheque it made sense, we also don't qualify for any daycare subsidy because he made just above the limit last year, without my income coming in we can't afford the rent on our place anymore, and we have to move into my parents home (which is big, and not a huge deal since we were planning on buying the house from them in 2 years when they retire), but now the clients that followed me to my home will not be able to see me anymore either because the house is quite a bit out of town. all of this has me pretty stressed out...and I'm not going to lie, I've NEVER wanted to be a stay at home mom, I don't enjoy it, I enjoy making my own money and going to work every day, right now I feel I'm paying off student loans for nothing. to top everything off I gained a lb 2 weeks ago which really upset me, and the next week I had some really bad appendix pain which ended up as being diagnosed as some pretty bad constipation because I was so stressed out so I couldn't work out last week (it cramped for like 4 days), and now this week I'm having a hard time getting on the wagon because I just feel depressed.

Has anyone else gone through something similar where you became an instant full time care giver and your whole life got flipped around, how did you deal with it? I love these kids, but I'm starting to really enjoy leaving the fiancee at home with them when he gets home from work so I can get out and do my own thing. a part of me also resents him a little bit which I know is bad. I think the biggest thing that's bothering me is that my dieting and workout has taken a back seat because when I'm stressed I crave carbs, and I have to seriously kick my butt to get on the treadmill....does anyone have any advice to shake a depression?