Do I have a right to be angry here?

Ok, so i'm on the board of a school club that does charity events, my other board memebers completly took over an event I was assigned to plan, and when I complain to them that they completly stepped on my toes, disrespected my authority, and bascially excluded me from the very group that i have been a dedicated member of for over 4 years(not to mention the year before i took on extra responsability when 2 out of 5 of our board members dropped out), they just said i needed to take a chill pill and just let it go because as of right now things are "Running smoothly"