I care about what people think about me, I even imagine and create stories about what they are saying or thinking about me at a specific moment. How to stop?

Ok today there is a masters graduation in my university and unfortunately i got a problem with my thesis project document and my graduation postponed by 3 months. So i already told for so many people that i will graduate today, so i went to photo studio and took a picture with rented regalia. What worse is during the photo session i saw the camera man smiling and in my mind i thought he is joking at me for not bringing masters regalia directly from the university, because universities give official gown. So i told him that i got a problem with my project and my masters graduation postponed by 3 months. After telling him i called one of my friends and she told me i shouldn’t have told the photographer my academic history, she said it is normal to rent masters regalia. Now i feel guilty at myself. How to stop this behavior?? In my mind i just create stories?