This is going to be a little harsh, but when women are stuck in guilt to the point they sacrifice themselves, people other than women and other women like them create that as a norm for all women. Bare foot and pregnant, and never complain, smile, you have children watching.

If you toilet was dirty would you clean it. If the dogs water bowl was empty would you fill it. If the garbage was full would it go out. Treat yourself as well as you would your toilet, dog or garbage. Yes you do have children watching you. Do you want them to understand you are an important person, a real human being, that needs a nap, or a book to read, or quiet time, or a whatever you need. They have needs, they get their needs met. How do you explain to your daughter, your needs get met until you become a mother, than you are just a family slave with no recognizable needs. That is going to make her really proud. She has a slave not a Mom. She can grow up to be a slave not a human being.

Making time for yourself is easy. Letting go of the guilt is hard if you view yourself as a sacrificial entity not worthy of rest or pleasure. Changing the way you perceive motherhood is easier if you think about what you want your daughter to know about motherhood. I wanted my daughter's to know, they can't take care of anyone else effectively until they could take care of themselves. You can't give what you don't have. So, take time for yourself and tell your children this is time for you to relax, or get a sitter if they are to young to understand. Or swap babysitting time with a friend. Or let their Dad play with them.