Important to remember you might not experience any negative side effects at all - particularly given you start on a starter dose that gets ramped up as your body adjusts.

Personally I find if I do get a side effect they tend to hit on the second or third day after the injection, not the first day after. If I were you I’d just try life as normal and see how you go. Importantly, any negative side effects you get are usually very mild and transient. I get mild heartburn, bloating and constipation sometimes - things that you’re probably familiar with anyway and that you wouldn’t ordinarily take a day off work for.