My Terrible Bug Fix that Wasn't Really My Fault

So here's the thing. Last week at work, I was working on this big feature for our latest project. It's supposed to help clients track their projects more efficiently. Anyway, I spent like three days debugging a really tricky issue with one of the backend APIs. Every time I thought I had it figured out, something else would break in an unexpected way. I finally got it working yesterday and felt pretty good about myself, you know? Maybe took a little extra coffee or two to celebrate. Fast forward to this morning when my manager comes up to me looking all serious. Turns out the fix I thought I made actually caused some other part of the system to crash randomly. I'm not kidding, I had no idea it was going to do that! Really? This thing works perfectly fine on my dev environment and QA passed everything too. But apparently, one client reported their entire dashboard freezing up right after the update went live. Big mess. So now there's an emergency hotfix rolling out as we speak and everyone is treating me like I'm the one who caused World War III to break out in our system. Yeah, okay, maybe I should've tested it a little more thoroughly before pushing it live but still, this isn't exactly my fault either. Anyway, now I just feel like an idiot. Probably won't admit any of this to anyone at work because no one would believe that the bug wasn't completely my fault anyway.