Seasonal birth control & lackluster workouts?

So ladies... does anyone else here take seasonal birth control and feel less than enthusiastic during workouts in the week or two leading up to "shark week"? I find that when I run in the week or two before, I'm slower even though I feel like I'm exerting the same effort, and I'm more tired when I finish my workout. Is there anything you do to boost your energy during this lackluster period (pun intended)?