Training with speed and power is okay for a small percentage of your training time if you train slowly without kinryokyu (sort of "brute force") but kokyuryokyu (force as natural as breathing) the rest of the time. Adding speed and power to a mistake just exacerbates the problem.
Try this...train slowly and gently, but with proper rhythm and get up from the ukemi quickly. Waste no time in between.
Falling down is easy, it's getting up that can be hard work. All activity during practice should be relaxed. Keep a lively but relaxed pace.
Periodically, let out the stops and "test" your ability to stay relaxed while going fast.
Safe and Happy Holidays to All.