Single Mom Needing Help

Hi my name is Jennifer I am a single mom of 2. I have ran into some very hard times and dont know what to do. I  dont receive any assistance from my childrens father he is absent. Right now its almost time for school and the schools are requesting money for things I dont have money for also the kids wants new school clothes and shoes. I am at whits end. Groceries is the main concern in my home. I have a 12 yr old daughter and a 9 yr old son. I dont want to seem like a failure in my kids eyes I sometimes just feed them and go without but I am getting really depressed and discouraged about  this. Please help me every little bit counts.