Is there a reason why you've stopped taking antidepressants? Asking respectfully, not in an attempt to have you justify your decision, because why would you have to.
Personally I'm an atheist, and thus (by extension) probably a bit of a nihilist - once I'm dead, I'll cease to exist and nothing really matters to me anymore. This means that once I've been gone for so long that nobody remembers me, I've long stopped caring.
I still try to live the best possible life. Because while the world in its entirety may not notice my existence, I certainly do, as does the tiny part of the world I interact with, and I intend to make the most of my time here.
People also tend to underestimate the impact they have one other people's lives. Ask anybody about people who have influenced them, and you will get a huge list. Ask the same person about a list of people they think they have influenced, and the list will be much, much shorter.
Until somebody explicitly tells you that you've had an influence on them, it's hard to know about it.
Ever since I've got step kids I can't stop worrying about what they'll learn from me and whether I'll be a good influence or the one they'll point their finger at in therapy session or on true-crime TV one day. So far they appear to turn out great, and every time they say or do something that they might have copied from me, I'm still in awe.
The same is true for other kids in the extended family, students that are unfortunate enough to be mentored by me, friends in need, ...
I'm also prone to worrying about pretty much anything (IT professional with a focus on security - not sure whether it's an occupational hazard or my tendency to worry has steered me to my current job).
Personally I've found that categorising my fears/worries helps tremendously.
If it's a rational fear, it should be something tangible and I can look into steps to alleviate it.
Our stock of food, water, fuel and medical supplies f'r instance should comfortably get us through any natural disaster, pandemic or power outage than can realistically be expected.
Irrational fears are difficult, as they tend not to be impressed by the fact that they're irrational and there's nothing to worry about. But I can still try and find other ways to alleviate them.
For example when I was a child there was a time when we were piss-poor, and I still worry a lot about money even though we're relatively well-off now and my job is very secure. In these situations I've found that it helps to look at our well-stocked pantry, so that something in my animal brain sees the abundance of food and stops worrying.
If it's something that doesn't affect me directly but still bothers me (e.g. the Ukraine war), is there any way I can help? For example make a donation, influence my country's politics (tough one in 'neutral' Switzerland at the moment), or anything else that makes me feel like I've made a difference?
Also, do keep in mind that most media paint an incomplete picture of what's really going on in the world. Headlines such as "Boyscout helps old lady cross the road" or "today has been a rather nice and uneventful day" just don't make for good visitor numbers.
Enjoying the small things can help. Mindfulness, as in "the ability to appreciate the small and seemingly insignificant things", is a wonderful tool to combat existential dread.