do you remember what version your save is from
That bad ending became a reality in v23.06 iirc. In regards to your problem, try reloading a saved game where you didn't OD'd on the blue pills, or if that isn't possible then you'll have to restart the game again.
I believe my saves were from 23.4.0f and I updated it to 23.6.1b which is when the problem started.
All my recent saves seem to have the overdose bad ending, and I even tried a few of my less recent saves from a couple of months ago and I also got the overdose bad ending.
I haven't tried all of my saves, but it looks like they all will probably have the same issue since whatever I did to trigger the bad ending seems to have happened a long time ago.
The only other thing that I think might be triggering it is that I have cheats on, so maybe it's triggering because of the combination of cheats I have active?
I think I activated all the cheat options simultaneously, so maybe it has something to do with that.
If that's not it, then I really will have to start my game over.