Just because you aren't given the credit and haven't been recognised for your work doesn't mean you have to give up or stop. You don't always need credit, other people do not always have to know what you are capable of doing as long as you do.
"Why does it hurt so much?" "Because it matters. Because you love with a tenacious love. Hurt is just the predecessor of love and anger is just the predecessor of hurt. You have a deep anger because you have a deep love.