Letting Go

So, part of me has to let go of some guilt that comes with being a mom. Right now, I have no problem going to the gym daily or almost daily because I know I have a ton of time with the boys, but when school starts the guilt kicks in....and I quit going. I have to let go of the guilt of working out for an hour when school starts again, I have to look at it like this, what is an hour each day of me not being with the boys if I am not around later to see them get married and graduate, etc.? I think they'd rather have me around than spend an hour with me for a short time, make sense? Plus, a happy & healthy mom is much better to be around than an unhealthy & sad mom.