Stress

I am unhappy at my job after only working there for two weeks, and I’m a full time student. My job knew that before hiring me. I start a summer class for college in may and need to know if my job will work with me on my availability but they are angry I have to change it and won’t give me a definite answer. What do I do? It’s making me so mentally exhausted and heightens my anxiety. Which has started to cause anxiety attacks again.