I don't think scaling back your exercise would cause wonky cycles. If anything, hardcore exercising has more of an affect on your period being unpredictable, delayed, or missing altogether. Mild to moderate exercise shouldn't cause your cycles to change drastically from everything I've read.
Stress can mess with your cycles, though. In a big way. Maybe that's causing some of the irregularities? TTC IS super stressful, as we all know.
I hope things regulate soon.
