Mommy Guilt?

It's a question because I'm not sure what it is. I mean, I know what it's supposed to be; that anguish you feel as a mother when you leave your children to go to work. It's supposed to be that tugging of your heart strings that comes with the reality of someone else having to care for your children. You made these kids to fill some hole in your life and now you're abandoning them to make a little cash. Or a lot of cash. Or just enough cash to make you feel like a grownup and not solely a mother....That's what most moms would define it as.
But here's the deal. I've decided I don't like this term. I don't think it's fair or just or doing my children or me any good to admit guilt for what I have and need to do as an adult.
My kids have two parents that work hard: Their dad loves them so much and wants so badly to be the best provider he can be. He quit his job and went back to school full time to get his PhD. He realized after 7 years with a good job in his chosen field that he wanted more, that he deserved more, and in order to get more, he had to pursue an advanced degree. Their dad is a full time student, a smart man who does more than most to better the future of his family.
Their mom works hard too. I have two part time jobs - from home - so that I can do two things. One: be with them, raise them, train them. And two: provide for my family financially while my husband pursues his advanced degree. We agreed on this path nearly 2 years ago. You can read more about the start of our crazy journey here. 
But here's the point. If I constantly focus on how sad I am to leave my kids when they go to their child care providers so I can work, I'm doing them a total disservice. If I've chosen this path then I need to be confident when I leave them. I need to be an example of hard work. I have to exude faith in my life decisions. Otherwise they are learning that work is an obligation, a hassle that we have to do, but don't want to do. And then what? My kids grow into mediocre adults and find mediocre jobs that manage to barely pay their bills and afford them the life they've been stuck with. I want better for them. I want them to learn that mom and dad love them so stinking much that mediocrity is not an option. If Ricky comes to me at 18 and says "mom, I want to be a plumber" my response to him will be the same if he chooses teaching or medicine or law as his future. And it's this - do what you want, but do it the best you possibly can. Don't settle. Ever. You're better than that. You're smarter than that. I've made sure of it. I worked hard so you would learn how to do the same and the value in it. You don't have to rich, but be happy. And the best way to be happy is to be confident in your choices. Find a life path that fulfills you and betters you as a human being, as a citizen of this world, as a partner, as a parent. Because otherwise, you're wasting what you have, what you've been raised with, what you've been blessed with.