To shrink your sweatpants, fill a bathtub with water and add in two cups of white vinegar.
Put the pants in the tub and let them soak for about twenty minutes to an hour. After, take them out and air dry them (no longer than 60 minutes).
After this, your sweatpants will have shrunk down to a tolerable size.
Another trick is that if you wash something in cold water it shrinks less then if you wash it with hot or warm water. However, the opposite goes for colors not bleeding into other clothes being washed together. For example, dark colors are more likely to bleed.
So this is how to shrink sweatpants.