Is it bad if I skip exercise one morning out of the week to just be lazy & read?

That really depends on why you are skipping. Has the week been tiring? Do you need more time for yourself or are you so busy that you can’t make time for exercises? If so, then you can feel lazy and read because this way you’re caring for your mind, and you can replace the exercise with light stretching for a few minutes. But if you’re skipping simply because you don’t want to exercise, try to exercise in the afternoon or the night instead of the morning. You won’t feel motivated to exercise every day, it’s a matter of discipline more than anything.