Am I in the wrong?

So I have a Dr. Appointment on the sixth. My girlfriend is off that day and is upset that I wanted to go on my own. Told her she could come but I wanted to see him alone and she's upset about it. Said it scared her because I need it to be private. Why on Earth can't I see the doctor alone? What's the big deal? She's even gotten upset when I've wanted to play a game on my own. She pouts super hard. Even though the majority of my time is spent with her, doing whatever together. I just don't understand at all.
Am I in the wrong?
Post Opinion