When to give it a rest?

carriempls

I started Power 90 on January 14th, so I'm in my 4th week. Previous to starting, I hadn't been exercising for several months. I take public transportation so walk several blocks a day and I always take the stairs at work but I have a desk job and was not active otherwise. I'm not foreign to exercise altogether (I've trained for a run a 10 mile race, have done yoga regularly, etc.) I'm just out of practice right now.

I'm keeping up with my workouts just fine, alternating circuit training and cardio 6 days a week. My problem is achey legs. I have really tight hamstrings and calves. I certainly expect to have some muscle aches as I adjust to the routines, but I'm wondering how to know what is OK/normal and what's too much. The last 2 weeks my legs have been bothering me off and on to varying degrees. Last night I woke up several times from it bothering me so it's affecting my sleep.

I try to not push TOO hard when exercising, hitting that comfortable edge where you feel it but you're not shaking from the exertion.

I don't want to stop the program, but I don't want to risk injury either. Any thoughts on how to proceed? Should I modify the workouts? Take more than 1 rest day a week? Just buck up and keep going?