How to hide going to therapy?

[Der/die AtheistIn]

I am currently a student at Graz and made a therapy appointment at the psychological department for students. It's  during vacation, so time shouldn't be a problem, except that my parents want me to come home during vacations and I really don't wanna tell them I'm going to therapy. I could lie that I have school work, but it's between semesters and most probably I won't have the same classes in the second semester. I know some people in Graz, but I just met them and don't trust to ask them for advise yet. If I lied that I want to go to a party or meet a friend, they might still insist for me to come home. My parents want to plan when to get free from work, so that they can take me home. There is also the fact that I want to solve my emotional problems as quickly as possible, I don't wanna postpone the appointment. What should I do?