Work help!

I recently started a new job. I asked for 20 hours max since i’m taking summer classes as well. Well they scheduled me 12-8, 5 days a week. I have no time to do school work and i’ve had three panic attacks this week. I’m not sure if i can finish the rest of the week there i might quit. I’ve had jobs before but only worked 2-3 times a week for like 5 hours. what should i do? real college classes start in a week.