You specifically mentioned that you are having a hard time keeping up with what is going on and "actually RPing through it."
Combat and RP are separate ideas. Combat moves too quickly for any meaningful RP to happen. Combat is what happens when people are done talking and the time has come to act. At that point, the "actions" are totally scripted.
Your character's ability to express themselves is pretty much limited to what you read in 'help combat'.
They are either 'attacking' , trying some sort of 'disarm' or 'grapple', changing a 'posture' or trying to 'flee' and escape. The art and science come in with knowing when to use what, and against whom.
I have only been in combat about half a dozen times. I have only 'won' two or three of those.
Grizz's suggestion to go back after the fact and review it is a good one.
There are also ways to test your combat skills against other characters in the game in a cooperative way.
As others have pointed out, after a while you will learn what the various combat messages are saying without having to read the entire thing. I am not at that point yet. It is all very new to me.
To get back to your original point about RP. The most "RP" I have managed to get out in combat is to scream for help, or curse my assailant. Usually in brief, two to three word phrases.