Should I quit my babysitting job?

I am 8 weeks pregnant, and I watch 2 little girls for $125 a week. Sometimes it is 6-4, others it is whenever their piece of crap mom shows up. First off, every other sitter I know charges 175 a week for 2 kids, so I'm giving her a discount. The girls's clothes don't fit them, they come dirty every day, and have been terribly sick for 3 weeks out of the last month. When they are sick, we are sick too.(I have a 2.5 year old). I'm just torn because I know the girls aren't being taken care of, the mom won't take them to the dr for a sinus infection, and won't buy them cold medicine, but she smokes like a chimney. The 3 year old I watch weighs 65 pounds, and is wearing 3t/4t clothing. My daughter will be 3 in march and weighs 27 pounds, wears a 3t.I am just tired of all of this, especially being sick. I think she is neglecting her children by not recieving medical care and by them not having clothes that aren't belly shirts. Should I quit or report them to social services for neglect. Thanks for any help.