Is working on Sunday a mortal sin?

Alright, I am 17 so I don’t have a family to take care of. I work to pay car insurance and gas money. That’s about it. Now my boss has me working Sunday 2-9 pm so I don’t miss mass. I work in a restraunt as a dish washer. It can be hard work. Is it mortal sin to work on Sundays under this situation? I asked my priest and he said that unnesasary work is forbidden but in my case it is nessasary to work Sundays because restraurants need to stay open Sundays in most cases to make money. I really do not want to work Sundays if it is mortal sin. If this is mortal sin would it not be mortal sin if I work less ours? Like 5:00-9:00pm? Thank you!!

These links should be helpful for understanding what the Church says about working on Sunday. If you have any further questions or concerns that are not answered by these links, please contact Catholic Answers directly.
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