My heart goes out to you; single parenting is one of the hardest jobs imaginable. This is increasingly common today, however -- and one reason I wanted to print your letter is to make all of us more sensitive to the plight of single parents (both mothers and fathers).
God knows your situation -- and I want to assure you that He cares about you and your children far more than you can imagine. He wants to give you wisdom to deal with your challenges, and He also wants to encourage and help you be the best parent you can be to your children. That's why I encourage you to commit your life and your family to Jesus Christ, and to turn to Him each day for wisdom. Remember, God gave your children to you and He loves them. The Bible says, "Sons are a heritage from the Lord, children a reward from him" (Psalm 127:3).
What can you do to ease your load? First, seek out practical help, both for your children's care and your daily household tasks. (Other single parents may be able to advise you about this.) Second, don't let your frustration boil over into verbal abuse or bursts of temper, but let your children know you love them -- openly and often. In addition, don't get involved in unwise relationships because of your yearning for help or comfort; this will only hurt you.
Above all, teach your children about God's love for them and His will for their lives. Seek out a church also where Christ is honored; many have excellent programs for single parents.