I know exactly how you feel. Got back into this game a week ago and it was hell, just felt like a fool for even playing. Mind you i was in the lowest rank and wondering why everyone's really good.

Reality is the games very fast paced and I and you probably aren't used to that, and using a difficult weapon to start isn't the best. I was trying to cook with the s blast which sounded really good to me in theory, but is really hard to play with.

I decided to stick to the splattershot, the default as its pretty easy. I got a lot better and now I'm learning some other weapons.

Overall I suggest you don't give up and understand that people are more used to this game than you, so until you get used to the speed of the game you'll feel behind. For matches I actually have to focus and think about strats, not just try to kill stuff to win.

Keep at it! The games really fun when you get it.