Our heavenly Father understands our disappointment suffering pain fear and doubt. He is always there to encourage our hearts and help us understand that He's sufficient for all of our needs. When I accepted this as an absolute truth in my life I found that my worrying stopped.
One thing my dad always told me was he would make sure I always had what he didn't have. He couldn't play basketball because he didn't have tennis shoes - so I had five pairs of tennis shoes.