I'm off this weekend, it's the first full weekend I have had off in a while as I usually do overtime one day each week (generally work Mon-Thurs, have Fri off, then overtime Sat or Sun). This week I did overtime on Fri so am having 2 days off in a row. An overtime shift has come up and work have sent out several messages asking pleading for help (and offering additional pay above and beyond normal overtime rates). Not many people are qualified to do this particular role that needs covering today, and I am one of them. If no one picks up the shift the workload tomorrow will be huge and it has knock on implications for the rest of the wider team. I feel like I should go in, but I don't really want to (and resent the manager putting her plea on facebook as it is making me feel even more guilty). Am I wrong for not wanting to go in?