Nanny Troubles

I just knew that I was going to get screwed over by the family I nanny for. When I started there I was told that I would get my minimum 25 hours a week that I specified in my ad. I was going to watch the two kids for the inbetween time that one is going to work and the other is coming home from work. I was also told that the old child is on medication. This is what I wasn't told:
The parents were seperating and the children were not handling it very well
The child on medication is not on medication for ADD, but antipsychotic medication AND he is very violent

I found all this out very quickly of course, like the second night there. I have stuck through it and have been there for over a month. It is very obvious to me that this family can not afford me, but the fact that they have very difficult kids makes it hard for me to justify taking anything less.
So, three and a half weeks in the mother comes home crying. I can be very compasionate to people I know when they are upset, but people I'm not really close to just makes a wierd situation for me. She explains to me that she is taking a huge paycut ($3/hour) and now she'll only be work for 50 cents and hour after paying me. I honestly felt bad, but I could not give her a discount considering her kids. If these were normal children, I could have done it.
Anyway, I finish up the week. I start to actively look for a new family to nanny, I just had a bad feeling about this. Not to mention, my patience was becoming very thin. I do not have the capasity to handle these children anymore, and I have to live with the guilt of taking my child into an environment that is not very safe. The medicated child has actually threatened AJ twice.
Well, I start this week. I find out the parents are back together... that honestly is a great thing. The younger child was having a lot of anxiety over his dad leaving, and he needs his family together again. BUT... calculating my hours out, I'm not going to get my minimum of 25 hours. It just isn't acceptable.

When I screened the phone calls for nanny jobs, I didn't want to take this job. It wasn't what I wanted, but the job started right away and I felt bad for these people. They needed a nanny and didn't have anyone.
Why don't I listen to my gut? I knew I wasn't going to be happy here, and I just knew I was going to be screwed over.