Need Help Paying My Bills!

I am a struggling mom trying to make ends meet. I don't sit around taking advantage of the state. Matter of fact I get no help from them at all except some medical on my kids. You see, I'm one of those that fall in the middle of the road. I don't make enough to make ends meet but at the same time I don't qualify for much assistants. I've worked the same job for almost 7 years and only make a little under $700 per month. Pretty sad considering I work for the state. I've worked hard to put a roof over my kids heads but find it hard to just pay the utilities and groceries. I've been a single parent of two kids for almost 12 years and get very little help from their dad. We have had lots of medical problems. One of my kids has had over 15 surgeries and we are looking at another one before the year is up. I'm currently looking for a better paying job but to no avail. I don't understand...I only want to be independent and be able to give my kids what they deserve (like school clothes and shoes.) I have lots of skills but always fall short of getting that better job. I have my own opinion as to why...I'm a little overweight and it seems like the "Barbie" looking girls get the jobs regardless of their experience.
So, if you have some loose change laying around and can spare the least little bit, it will help our situation.