How can i be treated this way it is not FAIR

I am Daryl Ho from Maris Stella High School
I was the player of the last match as the overall score was 2-2 . I was playing the final set and the score was 29-29 .After I serve the ball my opponent did a drop shot and I was almost unable to take it but still, i dive towards the shutter and hit it trying to get the shutter over the net.At first, the ball hit the net. The opponent thought that he had already won but the ball unexpectedly cross over. The opponent was surprised and tried to reach it but gave up as he was unable to reach it .I became excited and go to the net to shake hands with the opponent.
My friends rushed to me and hug me then we started to cheer. Soon, we were about to leave to
collect our bags when Anglican High started cheering. I was puzzled as to why will they cheer if they lost to our school? We walk towards them and ask them what had happened then the Umpire told us that the shuttle that I hit was out. I was very shocked! Soon after we got out of the hall, I felt upset and cried as I have been training and fought very hard till the end .I can't accept the fact that I lost .I hope I will have my justice back!