MeeDee,
Really good question. But I have to ask one back to you. Are you trying to prepare yourself for the future meeting with you and your girlfriend? It is only normal and natural to wonder and try and go through what may be said or what she will say and then you try and conjure up a response back. Very normal to want to do that. I would be careful in trying to do that too much.
When you do meet up with her again, you want it to be a healthier you and you don't want to be in "anticapation mode" when meeting with her. You want to be in listening mode and then after deeply listening to what she has to say, you give an honest response back. If this relationship is going to survive and get stronger, honest and open communication will be the only way.
To try and anticaptate what she will say and then try and think, what will I say back, can take away from you being "all there" while you are together. Your mind will end up racing thinking what is the best way for me to repsond, instead actually listeneing to what she is saying and sharing your true genuine feelings about what she is saying.
You may have asked this just because... but I do wonder if there is a connection to your upcoming meeting :)
Clear your mind and thoughts. Think about what you want out of a healthy relationship. Try and not focus too much on what you think she will say and how you should respond.