These are common complaints but particularly so for mums whose days aren't their own anymore and who struggle to find time to take care of themselves.
Yoga doesn't have to be a weekly class, although this is often the best way to ensure you actually make it on to your mat at least once a week and spend a good hour doing a full yoga practice.
Yoga can also be fitted in to your busy schedule, requiring perhaps as little as 15-20 minutes a day to help keep you physically, mentally and emotionally supported. Think of how you might tend to a garden - keeping it tended to little and often is as good, if not better, than a big session every now and again to keep it all under control.
A practice that is customised for you is ideal, incorporating some physical postures to help energise the body, stretch and release tension, strengthen the posture to help alleviate aches and pains. Plus perhaps some breathing work to settle the mind and restore balance, and perhaps even meditation if interested (which has well known stress-relieving and healthful attributes). All of these practices will help you create and maintain some well-earned space for yourself, and can be fitted in to those small pockets of time once the kids have gone to bed, when they are napping, when they are watching tv, or before you go to bed.
In my group classes I always encourage students to try some yoga practice at home if they are interested. Part-way through the term, I'll often offer them a small handout with a short practice to try for themselves at home. Sometimes students keep it up and come back weeks or months later reporting how much more benefit they get from yoga once they have started regular practice at home.
Of course a daily healthful practice doesn't just have to be yoga, there are other things that you might find you enjoy that keep you motivated to continue with it. But what better way to nurture your health and wellbeing than by giving yourself the gift of a short yoga practice a few times a week to help maintain balance and health in your life.