Joy is a beautiful name. You are so fortunate to have been named Joy. Obviously, whoever named you took one look and decided that your birth has made her or him exceedingly glad, happy, elated, so he or she named you Joy. The word joy names a feeling. It is a noun, not an adjective.
I say this to inform those who are critical of your name. I do not understand why they would waste valuable time and energy being contrary. It is negative and unnecessary. If people do not have anything positive to say, then they should not say anything about your wonderful, fantastic, magnificent name Joy. Stay strong and be proud. Ignore the haters, don't waste your valuable time being annoyed. Just remember that Joy is a gorgeous name that you are very fortunate to have.