I need a fish expert, goldfish upside down...?

To my dismay i noticed my goldfish was swimming upside down yesterday morning and it continues through today, and right now. It was still swimming a bit, and breathing. I immediately umed it was dying, however, because it seemed its tail was progressively getting shorter due to the other fish attacking it. Then, I read online about swim bladder syndrome, and my goldfish fit all the criteria. He eats on the top of the water where he can suck air, he eats a lot, and had a bloated stomach/swim bladder. Help? He's still alive, but I don't know what to expect, if the swim bladder doesn't correct itself within 48 hours, what should i do?