Is it normal to be afraid to cry in case you can't stop?

I spend my whole life being the bread winner, the disciplinarian and basically the 'strong' one in the family. However, no-one knows that I'm just so unhappy, I'm afraid to cry in case I can't stop. I don't want those around me to lose their 'rock' but sometimes I need someone to be stronger than me but I don't have anyone.

Is it normal to feel like this?