Getting over on-call anxiety
You've joined a company, or worked there a little while, and you've just now realised that you'll have to do on-call. You feel like you don't know much about how everything fits together, how are you supposed to fix it at 2am when you get paged?
So you're a little nervous. Understandable. Here are a few tips to help you become less nervous:
The first thing you need to internalise to do well on-call is: it's not your job to fix every possible thing that could break.
Your job is to make sure that someone fixes the issue.
You can always page someone else with with more expertise to fix the problem (ideally, once you've investigated the alert, and can provide the next person you page with context to get them started).
It's pretty common to have a loud, scary "nuclear alarm" style ringtone for your on-call pages. Or worse, using the same ringtone as the rest of your calls.
You're going to want to use a different ringtone than the rest of your calls - it lets you know immediately whether you're going to need to focus, or if you're about to have a chat with your Mum. On top of that, it helps you avoid associating your phone ringing with anxiety - a fair chunk of the anxiety comes from not knowing whether the call is you being paged, or just another telemarketer.
I'd also recommend using a gradual ringtone that gets louder and louder - this is more of a personal preference, but I find the loud alarm style ringtones create an unproductive sense of panic that gradual ringtones don't.
Like most things, on-call (should) get easier as time goes on. Eventually, you learn the processes (and help improve the documentation as you discover gaps), who to escalate to when things get really bad, and so on.
While the anxiety over getting paged never completely goes away, you gain confidence that you can solve any issue that arises, making the anxiety much easier to manage.
Also know that your team is there to support you - particularly your manager. Chances are, they've guided your colleagues through starting on-call as well, and can help address any concerns you may have about going on-call.