I have two kids under 6 and while it was very hard for about a year or so I realized that I am a lot happier than I was before I had kids, even though I do an order of magnitude more chores. Then I realized that this is the reason I am happier --- I work; and I don't mean I work for an employer, I work for my family, my children, my house. This is what makes me happy.
There is an ancient Greek saying: Not working is the root of all evil.