I initially needed to quit for financial reasons too, but then I started to feel the health benefits, which actually I needed just as much but had focused more on the financial.
I promise you will start to change how you think and feel as a little more time passes. Right now you are probably feeling fed up because you have to quit because you need the money for other things, so effectively it is a forced quit.
Try to see the positive side, thats it's not just that your daughter needs braces, but that you will soon see the other benefits, and there are many.
The first few weeks can be difficult, you just got to do whatever you can to ride it out. I found early nights helped, and also listening to relaxing music on youtube helped.
As said before lots of little treats, and some nice foody snacks.