My Dying Fish....

So...my fish is dying. For some weeks now, I have noticed that he is bloated, and he has been getting progressively worse over time. I have expected him to die any day, and today he is definitely showing signs of dying. He is not dead yet....his gills are still moving a little, and if you move the bowl, he will move around a little, but he is swimming erratically. I feel....bad for him. I thought he was pretty old for a betta, but there are differing numbers regarding their average lifespan. Either way, I think I've had him for about one and a half to two years....maybe a little less. It seems longer than that, but it really can't be. I feel bad....I probably didn't take the best care of him. I try to convince myself that he was already half a year to one year old when I got him (and thus lived about three years, one of the average lifespan numbers), but I still worry that I could have taken better care of him. In any case, it is too late now.