V.S.
I’m sorry you’re going through this. Your friend sounds a bit immature and honestly, you can’t force the friendship. Although to me it seems from what you’ve said that it’s very one sided (you do a lot for her, loan her your things, etc) Do you really want a friend that takes advantage of you and is only around when she needs something from you? Maybe she’s pushing you away because she’s envious that you graduated from high school, are still married and have a job? It sounds important to you to figure out why she is avoiding you so maybe go to her house when you know she is there and talk to her but don’t be confrontational. If she is not willing to talk, just ask for your stuff and be on your way. Make new friends, real friends.
Your children need you too much for you to be worrying about what is going on with her one day to the next. You sound like a wonderful person! Don’t let this one person make you think otherwise! Here's a good quote for you:
"Never make a person a priority in your life, while allowing them to make you an option in theirs"
Best of luck!