Complete and Utter Defeat

Today was, quite possibly, my worst attempt at parenting. As I sit down and clear my head a bit I can start to understand why Madison has been acting out so much but today my blood was boiling far too much to understand. I have been telling Eric for a long time to cut Madison some slack because things at home are so confusing. Some days he is home, some days I am home, sometimes he's traveling for work, sometimes I am gone all day for school, there is stress from what is going on and I know the kids feel it as much as I try to shield them from it. There has been no consistency for so long now and I'm sure it's hard for the girls and even scary for them. When I see Eric getting frustrated with Madison it's easy for me to have empathy for her and try to calm the situation but today I couldn't find the empathy, at least not before now. I feel like a complete failure today. I think I have been so lenient on the kids since Eric lost his job so many months ago and letting so much slide that I have created this situation we are in. It's gone on so long that I feel completely defeated. If there is one thing every parent wants it is to succeed in being a great parent. Although I never felt like a great parent I did feel like I was doing "okay". I felt like I was doing a fairly good job but I honestly don't feel like that tonight. I have been making a lot of mistakes and now am at a loss on how to fix it.
Madison has not been listening to me or Eric at all. She will sit in front of us doing something she is not supposed to do and continue doing it even when she is asked to stop. The consequences don't seem to work and even if they do she pushes the limit so far it's exhausting and leaves me feeling furious. Today I took the girls to a playdate. We went to a house we had never been. Madison went to preschool with the older boy so she knew him but not really well. All morning she was pushing the envelope with me but I just thought she was excited to go to our afternoon playdate. It didn't take long after we got there that she started in. First she was cold outside so she begged to go inside even though I had warmer clothes for her. After that she wasn't happy with the movie that was on the TV so she kept telling me that until the host heard and had her pick another movie out. Then the real problem started. We were sitting on a nice leather couch when she started climbing on it and putting her feet on it. At home this is fine but they clearly didn't do this sort of thing and Madison knows we can't do this at someone else's house just because we can at our own. I was sitting right next to her and she absolutely refused to sit there. She was standing, jumping and sprawling out all over the couch. I was mortified. I kept telling her that she needed to keep her feet off the couch and sit down if she wanted to be on the couch and she laughed at me. I finally removed her from the couch and she just kept coming back to it. I was getting so mad. Then she started in saying how hungry she was. During out last 15 minutes there she probably said "I'm hungry" 20 times. We had just had a big snack outside and I said she would get a snack when we left but she just kept begging for a snack.There are so many other things that happened today but they all are along the same lines of just not listening. I don't know if this warranted the anger I felt (and am feeling all over again as I type it out) or if I'm just so stressed out that I am overreacting but the fact is my child does not listen to me. If you know my daughter it isn't like her to cause this much attention to herself in front of new people and in a home she doesn't know so this added to my frustration.
I'm just feeling really bad tonight and need to figure out what to do about it. I can't magically find Eric a job doing what he was doing and allowing this family to relax a little. I can't drop this class now that I'm in to it this far. I can't make my child listen to me and I can't make my stress disappear. I can't get rid of this anger I feel towards my child despite how much I love her. I can't even begin to get rid of the guilt I feel for the way I have tried to handle so many things or how I have let so much slide because I felt so bad about what was going on in our life. I feel like she is taking complete advantage of me (us) and it's 100% my fault. I can't imagine how to try and begin to fix this or if I have the knowledge or energy to even try. I just don't think I can do it all...I can't be a good wife, good mother, good student, good friend, exercise, cook healthy meals, clean the house, and on and on. I'm just feeling a bit overwhelmed tonight. Hopefully tomorrow I'll figure out some things I "can" do.