It is hard to see exactly how bad the situation is as an outsider, so in the end, you are the best person to answer whether you should find a new group.
Here is my perspective based on my experience of tabletop and some advice on what to do or think about.
Is this a toxic situation or a misunderstanding?
You say that you are not having fun playing and that after trying to talk to the players who are the problem, things didn't improve. This is a pretty big red flag.
It is not your job alone to try and fix the broken dynamic. And finding a new group that will be more fun to play with might be a preferable choice. The subreddit LookingForGroup worked very well for me for online groups on multiple occasions.
There are options for you if you still want to try working things out with the current group.
1) Stand up for yourself and talk to the other players.
This is here mostly for completeness. It sounds like you already did this and unfortunately things didn't work out.
2) Talk to your DM outside of the session and see if they can help.
While it is not only the DM's responsibility to maintain good table culture within the group, they are often in a privileged position to do it. Explaining the situation to the DM might lead to a few outcomes:
- They might be able to use their authority to resolve the situation.
- If the players in question are causing other problems at the table, they might have to leave, and you can continue the campaign.
- The DM doesn't want or is not able to help mediate the problem, but that might help make the decision to leave the group at least.
3) Talk with the other players in the group.
I wouldn't do this unless I talked with the DM first. If you feel like other players are unhappy with the group dynamics, talking to them about your situation and the fact that you are considering leaving the group might be a good idea.
If you are in a toxic situation, there is a chance that you might not be the only one in the group with the issue. Maybe you could look for a new group together.
As an afterthought, you mentioned depressive feelings. I don't suffer from the same issue, but I deal with fairly bad mood swings, which often significantly alter the experience during my D&D sessions. I've found myself feeling like things are not working and I should leave my group in the moment, but after more examination realized it was just a patch of really bad mood distorting the actual situation and my perception of it.
I am not saying this is what is happening to you. You shouldn't gaslight yourself into thinking there is no problem if there is one, but it might be worth examining while dealing with the situation. Ultimately though, if you are not having fun and don't see a way to fix things, you might need to find a different group either way.