Please allow me to correct your post:
Hey guys , I want to ask you a question.
What is the difference between these examples?
1) I should probably go
2) I should probably get going
The second one is a little strange for me.
Thank you in advance.
The form 'wanna' belongs in spoken language, not written language.
Capital letters are a necessary part of the written language, not an optional one.
And the answer? 'I should get going' is a very common, natural, informal, idiomatic way of ending a conversation. It has the same meaning as 'I should go', but it is less abrupt. It can sound a little rude and sudden to say, 'I should go'.
By contrast, 'I should get going' is a bit softer and friendlier. Whereas 'go' means 'leave immediately [to go somewhere else], the phrase 'get going' means something like 'starting' or 'putting myself on the road', which can be seen as a gentler way of ending the conversation.
I hope that helps, and I hope you don't mind my correcting the way you wrote your question.