Diagnoses matter, and they also don't matter.
Diagnoses aren't the cause of emotional and behavioral problems; they simply describe clusters of symptoms that generally hang together and generally respond similarly to the same treatment. Sometimes they also described related physiological states, but we're still in the early stages of understanding all that (and more). With severe mood disorders and disorders involving psychosis, it can be particularly helpful to tease apart what is what, which is a difficult process that takes time and lots of points of information in order to identify the most effective psychological and psychiatric treatment. I, personally, am not specifically trained in bipolar disorder and schizophrenic disorders, so I refer these clients to clinicians who are so trained, so that they can get the best treatment possible.
In my work, diagnoses aren't terribly helpful. What is helpful is understanding the whole person, the world they live in, and the life they've come from. What is helpful is understanding how they see the world.
When my clients ask me, "what's wrong with me?" as they very often do, the answer is never a diagnosis.
The answer always involves shining a light on all the experiences and contexts that have made life a struggle. It involves shining a light on why it has been difficult to make things better. Often people get stuck in a place where they only see their imperfections, their failures, their traumas. People get stuck in a place where they don't see the entire picture anymore, including the wonderful parts of themselves, their successes, their efforts, and those who love them.
People often have superhuman expectations of being able to deal with terrible situations, and they often expect themselves to cope and express emotions masterfully when they may never have had good models for doing so (which includes most people in the world, for the record).
"Depression" or "Anxiety" are not the problem, but they provide words to describe the states we find ourselves in at points along the journey. The pain and the struggle are clues that something isn't working quite right. They are signs that the gears need to be oiled a bit, or there is a crack in the windshield that needs some attention. What is wrong may, more accurately, be not having enough self-compassion, having unrealistic expectations for yourself, having experienced persistent dehumanization, or having experienced significant losses, for example, but no, there is not some fundamental flaw in you. You are not broken anymore than anyone else in this world.
There is nothing wrong with you, things are just hard. And there are things that can help get you through, ways of thinking about things, and different things to try that might make life less of a dark tunnel and more of an interesting and beautiful journey.