Can you get a masters degree in psych if you have a bachelors in creative writing?

No. Psych grad school is VERY competitive for admission and you don't have the "foundation" type of classes required to do a Master's. It's also very competitive to "work in psychology", especially with just a Master's degree.

Check the admission requirements for the program you want to get into. You don't have to have a BA in what you study for graduate school, however, the program will expect you to make up the deficiencies. Some programs are also highly competitive. For instance, I want to get into a PhD for Spanish Literature. I majored in Classics for my BA and Humanities for my MA. However, I do have coursework in Spanish Lit courses and I am a native speaker. Not to mention my MA thesis was related to Spanish Literature and I studied some of the languages required in the Spanish Lit program so this would still mean I have a shot. My friend majored in History but wants a PhD in Classics, which requires Ancient Greek and Latin. So she took an extra year taking intensive language courses after her BA. So while it is possible to go into a different field after your BA, you will be expected to make up the material you missed somehow.

Study for it. Just bc you have a BA in one thing doesnt mean you cant get a masters in something else. Go ask your counselor

"Creative writing". Why did you need to study for that.

Anyway, go talk about this to a school counselor, they have all the info you need.