I absolutely suck at close range combat. Any tips

I play on Xbox with a controller and I lose 80 percent of fights where the enemy gets up in my grill as any class. I've got the sensitivity up as high as I can with out making it unplayable but I just can't hit players who get close and strath/duck up and down/ dash around me. I end up using heavy and flamethrower if there is a lot of lights with dash especially if cross play is on as when they dash around/past me I'm dead before I can turn around and I think they know it. I try and place mines behind me to cover flanking. Any tips or is it just a case of trying to turn the sensitivity even higher. I just feel any higher and I'll just over shoot my mark in every aspect.