Meh Ive been there before.
I can tell you right now, You take this game too seriously if you get emotional at ALL when you lose.
Yeah it's a good feeling to win, thats a given. But to truly advance your skills and to keep your mental sanity, you really have to take losing with a grain of salt.
Take it from me, the first time I lost online against link I smashed my fist on my computer desk, Im ashamed to admit it but I did.
Nowadays if I lose in video games at all I just laugh it off, I also try to figure out WHY I lost and how to avoid making the same mistakes. Which is what sepperates a stagnant fighting game player from a competitive player who is constantly improving.
If you take a player like sheermaddness as an example, this is a guy with the perfect competitive mindset. He plays yoshi because he enjoys him, not because he's the best tier or whatnot. Also, Ive seen his matches and played him a few years ago, and Ive played him sometime in 2009, he's always improving his game and thinking of new ways to combo/mindgame/DI and so on.
You've got to have your mindset on "IMPROVING" not "IM GOOD AND I LOST BECAUSE -INSERT JOHN" or you should just quit video games in general or play RPGS or something.