Woah! 45min HIIT workouts 6x a week?!? I'd say hold off, buddy!
Lack of energy and excessive muscle soreness are definitely indicators of your body pleading..REST ME!
More workouts don't necessarily mean more weight loss. I wouldn't be surprised if all your "HIIT" workouts, (which I have to ask what they involve if they extend for 45minutes....) are signaling some cortisol excretion, which is a trigger for weight gain/lack of weight loss.
Try subbing in some heavy lifting twice a week, but NO MORE than 45 minutes, IF that! Crazy animal... what's most important is GAINING MUSCLE rather than burning calories. If you want to burn excess calories, just do some LIGHT aerobic work. Not super long HIIT workouts, six..times..a week..