My first nightshift job

So I was a usual day shift until my contract was cut short due to budgets, I have now switched to nights as it was all that’s available, I’ve done two shifts and already have felt a very sudden drop in mental health as-well as not eating and nausea. Is this just my body telling me this isn’t for me, or a natural reaction to the switch? Would love some advice as I’m honestly thinking about quitting a week in, I’ve never experienced this bad mental health in years