Why do I always feel guilty about not doing more for my family?

Unnecessary. You may be feeling guilt when it is not appropriate. Sometimes what feels like guilt is another unpleasant emotion stemming from comparing yourself to others who might be wealthier or better off in some way. It might help to make a point of being grateful for what's going well in your family. If you're already doing your best for yourself and your family you could be proud and not guilty.