My package has always shrunk during and after exercise, that is very common. I remember even back in school after swimming, for the rest of the day things didn’t look good. But yeah, maybe because thing are messed up down there anyway, the diversion of blood effects it for a while after.
I think it’s hormonal though, because i start feeling like shit too. Maybe my body can’t handle a boost in cortisol or testosterone or something. As usual, im just left guessing and could be way off.