I... uh... take no responsibility for this!!!
Dang, man - I'm glad you're OK. This is a testament to the safety of the buggies right there!
Since you're already at 38mph now, you can probably hit that magical 40mph mark with a 30mm carb (once you get the buggy back in good shape, anyway!) A 155cc kit and 30mm carb package with a ported head would probably give you more than enough to hit the 40mph+
Let's see how you feel in the morning. Those kinds of phantom injuries sometimes take a day or two to reveal themselves. You may find more damage in the daylight as well.
Sure am glad you're OK.