I work at a grocery store as the liquor department head, and next month everybody in management above me will be gone for 3 weeks. I am expected to essentially run the store alongside 2 other managers who are below me. I have a job opportunity elsewhere for triple what I make, but up until this point I've been treated well. Is it reasonable to feel guilty about leaving this job when they need me, despite it not being anywhere near my job to cover 3 vacations at once with no extra help?