from my perspective (American dialect):
To "get going" means to take concrete actions to prepare to leave. It can also mean "to hurry up." So, for instance, if I have a lot to do today, and I am dawdling over my breakfast and drinking my second cup of coffee, someone might say "you should get going!" But they probably wouldn't say "you should go!"
So "I should get going" is something I'm more likely to use when I'm implying that I have somewhere to go and stuff to do. "I should go" I'm more likely to use when I should leave. (For instance: we are at your house, we just had an unpleasant conversation, and I feel unwelcome: "I should go." I am at your house for a dinner party and it's time for me to go to bed "I should get going.")
Summary: "I should get going" implies I "should" because I have somewhere else to be, whereas "I should go" implies I "should" because it's important that I not be here. This is subtle but becomes more strong when we change "I" to "you."
As far as "I should be going," it's something I hear in movies but I don't personally say; maybe it is more British, or maybe it is just old-fashioned.
sometimes choices make you
It means that sometimes the choices you make influence who you become as a person.
As noted by @Sam I Am, this is not a normal phrase. It is designed to be the reverse of the first half of the sentence (you make choices), and seems to be ironically implying that while you expect to have control of your decisions, sometimes those decisions can effect (control) you.
In this case, it is also implied that these choices are especially important, hard, or have dramatic (possibly unexpected) results. Less obviously, it is likely implied that some portions of these choices are negative in some way (though this may not always be the case).
Example
During your childhood, you become a delinquent, and end up committing a crime that lands you in prison for 10 years. This choice may "make you" into a fundamentally different person than if you had not gone to prison. Perhaps you now feel compelled to work helping criminals give up their lifestyles (because prison had such a negative effect on your life) rather than if you had not gone to prison and become, say, a wealthy banker.
Alternate Phrasing
Is there any other examples or metaphors that could be meant by that phrase?
The closest I would say would be:
"You (We) are the sum (total) of (all) our experiences"
Meaning what you experience in life shapes your personality, outlook on life and general approach to living.
Best Answer
It is a metaphorical use of the verb "pick up" in its simplest sense of lifting something off the ground. Your sentences mean that this person has become passive and/or disorganized, sort of like a useless rag that is lying on the ground. So, yes, in a way, "pick yourself up" means "improve your game", "become active again", "work better". Another phrase that is used in these situations is "get your act together".