Yeah that's unfortunate. I agree that people can have naturally occurring shifts in their sleep patterns. However, you had a shift in sleep accompanied by racing thoughts, mood elevation, and reckless driving. Taken altogether you experienced 4 very classicly presented mania symptoms. 3 out of the four are not explained by sleep disturbances and you have a history of mood disorder. The most likely answer is you experienced mania.

I feel like maybe he's covering himself in case you decide to sue his practice for the crap diagnosis the assistant made. He even had a trained professional who witnessed the mania weigh in and is dismissing it. I wonder how your T will react to that. He is being extremely neglectful of your needs. I'd find a new doctor for sure. I think I'd also report him.