Hi my friend. How’s your week? Get up or get busy and accomplish something. My football team is playing our rival team today, come on let’s get up and at ‘em (A mother to a child who won’t get up) Come on, wake up, up and at ‘em

First of all, the literal, not contracted words would be: "Up and at them." It's a fairly familiar phrase in the US. It's original was apparently an English general at the battle of Waterloo. So, it's basically a call to action, especially action against some sort of foe. The carton hero Atom Ant's catch phrase when he was about to go into action was: "Up and at'em. Atom Ant!"

I'm turning 40 next month, have always lived in the UK, and don't recall ever hearing this phrase in my life. I can kind of guess its meaning but would need to Google it to be sure. Wiktionary says it's often used when waking people up from bed, similar to "rise and shine" - now this phrase I have heard many times, it's quite familiar to me, but "up and at 'em" is not, so don't be surprised if most native speakers look confused when you say this to them.