I’d like to add the caution that not all depressed, romantically unsuccessful, or crisis-prone people are misery pits, particularly since many such people are likely to assume they themselves are. If you have friendships that extend for longer than a year or two, you are almost certainly not a misery pit.
From the perspective of a person who might be a misery pit: one key is to avoid overburdening any single person. Cycling between three or four support people can be helpful. For validation-seeking, I’ve found social media works well, since liking a sadpost is usually less stressful for most people than comforting a sad person. It’s also helpful to prioritize learning how to create value for others. Try to have pleasant interactions with your support people (fandom, gaming, sharing jokes, talking politics, doing a hobby together, whatever) more often than you call on them for help. Consider learning a service-provision skill, such as cooking.