Ah, in that case it may have skewed your readings a fair amount. That, coupled with loss to trub, could account for a lot of the discrepancy between pre- and post-boil gravity. Not sure about the full 12 points, but it’s possible.
Your pitcher might be just fine. If you have a cup measure, see how it tracks. 4 cups = 1 quart, 4 quarts/16 cups = 1 gallon. Weighing it is better, though, if you have a good scale.