I think this can kind of just happen, where once depression gets that bad those types of symptoms can linger afterward longer than you'd realize. I've had 2 depressions that got low enough to experience some psychotic depression type symptoms, and it did seem like some of those symptoms kind of stuck around mildly as I was getting better.

For one thing, that negativity, those experiences of the world where you're sure people are hating you and talking about you, are still stuck in your head. It might take some more positive or normal experiences to kind of slowly finish "convincing" those thoughts to leave your mind. Also, even though a lot of depression symptoms may be gone, you've still been experiencing that constant berating of yourself by depression for a while... it may take a bit of getting back to life to build your self esteem back up, and while it's that low it can still contribute to paranoia.

I would guess stress also could bring back a (hopefully) temporary rise in those symptoms again. With work it would depend... do you think you're really just not ready, that it'd be too much stress and some time off would really help? Or do you feel like, once you get over the initial hurdle, getting back into the world could help you continue recovering and raise your self esteem? I know sometimes I may not "feel" ready, but pushing myself to get back into the world and not have too much time to think helps me continue recovery somewhat. At the same time, if you're still at a point where you're just not ready that's ok, too.

I'm sorry you're going through this, I know it's scary. Try to cling to the parts of you that are feeling better, remember that these are just symptoms you're still having. Do you see a therapist or would you be able to see one, or even just try some CBT on your own?