Kitty you poor thing.
You have to do what is best for you, which is the best thing for your family! When your more relaxed and content, your family will be too!. Finances can be a hard thing to juggle, but give centre link a call and see if they can help you.
You must see leaving work as keeping you and your family happy and healthy, not see it as 'being weak'. It a tuff decision, which makes you strong for standing up for what is best!

Take care of yourself and I hope you start feeling bettre REALLY soon!