Twelve-time Olympic medal winning swimmer Ryan Lochte stunned fans this week by announcing he has taken a $30,000-a-year assistant coaching gig with Missouri State University. It’s been a rocky few years for the champion after battling depression so crippling some days he couldn’t even get out of bed, he told The Post in an exclusive interview from his current home in Gainesville, Florida. Last August, he also went to rehab and he’s still in the midst of a bitter divorce from his estranged wife,