I Spied on My Kids' Secret Messages While They Thought I Was Offline

So, here's the thing. Ever since my kids got into their phones and social media, it felt like a constant battle to know what they were up to without invading their privacy. I mean, I don't want them thinking that I'm some kind of stalker parent or anything, but at the same time, as their mom, I have a duty to keep an eye out for any red flags, right? So one day, when they both seemed especially secretive and were texting back and forth incessantly while on FaceTime with their friends, something in me just snapped. And without telling them, I hacked into their accounts using the passwords that are stored in my phone's notes section (don't judge, it was for an emergency if ever needed). Sure enough, there were some concerning conversations about pranks they planned to pull at school and some less-than-friendly comments made towards a couple of classmates. Now, I know it sounds bad and maybe even overbearing, but seeing those messages gave me this overwhelming feeling that if I hadn't checked, who knows what could have happened? Of course, now the kids are upset with me for snooping and I feel like a terrible parent for having broken their trust. Am I being too paranoid or is it really necessary to keep an eye out when they're online so much these days? What would you do in this situation?