Explain to your employer your obligation to attend Mass on Sundays. Most companies make accommodations for religious exemptions. If your does not, then your position would only be sinful if you don’t have grave cause to miss Mass.
“On Sundays and other holy days of obligation the faithful are bound to participate in the Mass; they are also to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord’s Day, or the proper relaxation of mind and body.” Canon 1247
" 1. The precept of participating in the Mass is satisfied by assistance at a Mass which is celebrated anywhere in a Catholic rite either on the holy day or on the evening of the preceding day.
2. If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the liturgy of the word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families. " Canon 1248.
EWTN states that:
“Reasons such as the necessity to work to support one’s family, child care, personal sickness or the care of the sick, necessary travel etc. would excuse a person on a particular occasions.”
This is something that you must answer for yourself. Do you absolutely have to work that shift, and would not working it jeopardize your employment and ability to support your family?