Have you taken your temperature in the morning before getting up? If your metabolism is dropping too much, you might need to do a carb-up once every 3-4 weeks at least. I'm not sure how effective such infrequent refeeds are, but Par Deus seems to think it is better than not refeeding. The hard part is eating above maintenance calories then dealing sub-maintenance calories again.
Also remember that adding cardio is only slightly different from dropping calories. A caloric deficit from cardio will decrease your metabolism as much as a caloric deficit from diet, if not more. If you are not doing very much cardio, then cardio might be the answer. If you are already doing a moderate amount of cardio, then a combination of reduced calories and cardio is better than increasing cardio alone (depending of course on your current maintenance calories --- you don't want to go too low).
Sometimes cardio can literally have no effect due to its negative effect on basal metabolic rate.