Are there any happy single moms?

It's occurred to me that every single (alone) mom I know is not particularly happy with her life. I know they'd never regret having the child of course, but i'd really like to know are there any single, moms who are truly satisfied with their life? I'm in no way being judgmental, but if there's one thing in life I fear becoming it's a single mom, it just appears so hard and stressful.