Hello! I know where you are coming from. But if it is one mistake... look. Things can and do change. My advice would be to give it some time.
I live and work in what Donald Trump would call a "shit hole nation". For the past three years I have been increasingly suicidal as it has become clearer that things here are going to get a lot worse, very fast. My job is such that it is hard to get employed in the first place, let alone rehired. Nevertheless, I went back to the job market and ALMOST landed a job in the U.S.
I found out I lost the job for a really, really stupid and avoidable personal mistake.
Imagine my depression. It hit rock bottom. Not only had I blown my chance for a stupid, easily avoidable reason, I lost a chance to get my family out.
Well, a year later... turns out that the job wasn't such a plumb after all. It's already eaten a colleague of mine. Coronavirus set in with a vengeance where it was located. Worse, my partner would have been halfway through their immigration process now and Trump has stopped all immigration. I would be on another continent and they would have no job and be stuck here. This is presuming that I didn't get fired in the first year, at the very least due to being a new hire and CV-19.
Now, I am not saying "Cheer up! Things will get better!" I am still in the shit and still depressed. Still suicidal. (And this site is a HUGE boon to me. Just knowing it exists calms me down. When it went down for a couple of days a couple months ago, I had a panic attack and truly felt that I was on my own. And I hardly ever post here!) What I AM saying is that if it is just one decision that has fucked up your life, odds are it is not quite as fucked up as you think. I know that is cold comfort. I am still in a rapidly disintegrating country and there is no hope on the horizon. But it could have been so very much worse if I hadn't done the stupid thing I was ready to kill myself over a year ago.
There is no rush to kill yourself because death is inevitable. You can always do it tomorrow. At the very least, read up about methods a lot, plan a lot, make dry runs, tie up loose ends. If you are going to do it, try to make as small a mess as possible.
CV-19 has fucked with me because my "clean up" process (making sure everything is all set up for my partner, basically) is now on hold due to the pandemic. So unless I want to leave a huge mess for my partner — aside from the emotional mess I will inevitably leave them — I cannot kill myself now. This has me more anxious than ever.
(By the way, I hate "ctb". Not calling for censoring others, but personally? No euphemisms, please. I don't think I am violating a rule here by calling suicide "suicide", instead of some catchy acronym.)