Sick and tired
A lot of people say they're sick and tired, when really theyre irritated and frustrated. If you're not terminally ill, you're not sick in the way that you mean when you say sick and tired. If you haven't been awake for days on end working around the clock, you're not really tired. You're just irritated and frustrated with something.
People are not really sick and tired, they're irritated and frustrated, and they've been irritated and frustrated for a long time now.
Sick 'n tired
When you have become so tired of something/someone, that it is making you sick. Something that mothers often say to their misbehaving, ill-mannered children.
Mother: Tony, I am so sick 'n tired of your shit lying all over, that it has made me sick to the point of vomiting in last nights casserole. I just dressed it with ketchup, so fuck you!