From what you've written there is not much that can be said, there are a few disorders except depression like ScPD for example that could be the cause of this, but they exist always with other symptoms, so you should either seek professional help, and if u cant afford it, then do your own research, study different disorders, and study your own mind obsessively, and when you will have enough knowledge you will propably know what exactly you are. Many people in this community will say "you are just nd", but the thruth is autustic people are often really expressive with their emotions between their burnouts, and if it really started only 3 years ago there is a good chance that this is only some kind of mood disorder, and not neurodivirgence or something like ScPD/ASPD. But you have to be carefull while assesing that bcs with personality disorders like this, symptoms are often getting worse and better in different phases of life, you need to deepen the understanding of your childhood to make a correct diagnosis.
