I'm asking my girlfriend too many questions, it's like sickness, I don't know what's wrong with me... :(?

You are not the only one this happens to and most people that do this are insecure in their relationships. It will serve you nothing and in the end you will be alone. Work out the reasons why you are like this and recover from them. It is most certain you have been jilted in the past and have a difficult time with trust. You are also using the excuse of being logical to cover your insecurities, and this is called manipulation. I'm not quite sure why she hasn't caught on to this yet, but I am sure she will.