So, I'm about 95% sure Sealed is rigged(self)

Other users above have posted hypergeometric calculators for you to use. Surely a YouTube tutorial will assist you in using them accurately. If you can roughly estimate the number of turns you took each game, you can calculate the odds of mana flooding for each game. You can subsequently calculate the odds of mana flooding three consecutive games. It gets trickier to calculate the odds of mana flooding three consecutive times for 12 of 24 games, but is none the less calculable. The odds will be pitifully low, but still perfectly reasonable when you consider that thousands and thousands of magic games are played every day. You are the outlier, and without any actual proof of conspiracy, it's easy to assume that you're the unlucky player for the day. Again, I'll ask the question that you've so carefully dodged each time, why doesn't this happen to everyone? Why is it just you?

Edit: I sincerely wish you better luck next time. If it's any comfort, it is almost a statistical certainty that it will get better for you.