Am I being unreasonable?-work

So I submitted a return to work request end of July for beginning of September for three days a week Monday, Tuesday, and Thursday 8-5.30pm. I have never worked weekends. I have recently found out I’m pregnant and let my boss know (a miracle tbh as first baby was IUI). They rejected my return to work 2 weeks before I return based on they need evening and weekend cover (company shuts at 7pm) I never worked weekends to start with. The new people coming into my role have to work weekends but my contract says I don’t. At the moment they offer people on my contract double time to do extra at weekends so I’d be disadvantaging myself in the future if I was to do this. So currently at have no childcare for 2 days a week 😭

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