You are certainly dealing with some challenges as a single parent. My hat's off to you for working so hard at it. Let's begin with the importance of school attendance. Children who are enrolled at a public or private school should attend school every scheduled day unless they are ill or have medical appointments. The security of the routine that regular school attendance provides makes the job of teaching a child that much easier.
Education is like building a house.
A solid foundation is built, piece by piece. If one of the pieces is left out, the foundation will not hold. Every child needs to attend school each day to participate in the building of their educational foundation. Your child's teacher is clearly frustrated with his attendance problem. She has made a commitment to giving your child the best education that she can provide, but is not able to fulfill that commitment completely because his attendance is poor.