Before some armchair asshat brands you as bipolar, consider that depression is a natural result of effectively burning out the anxiety receptors/generators.
Too much stress, and you either lack the stress hormone generation, or you are desensitized to its effects.
Untreated anxiety results in depression. For some, that means a trip to the doc for some meds. For others, it means time to do something exciting, like start a new company.
Serial startups may be self medication. It may seem like you are coping well, but it may be a coping mechanism to make up for things you are missing.
At some point, and it may not be you in particular, but many in the same position will have something give out. Physical or mental health or something else, it doesn't matter. Basically anyone living in a first world country (by any definition) already has an abnormal life, and living on the edge is really just taking an extra chance. I suspect there is no real "issue" here other than people deciding that "toughing it out" is somehow "being true to yourself". The normal stressors of modern living plus the added stress of putting your life on the line, basically, eventually put people like you at higher risk.
If you wear sun screen, watch your diet, or in any fashion try to look after your physical body, but neglect your mental health, it seems you are willing to accept an abnormal life as normal, when it's not. To individuals, yes, but to humans in general not in any sense normal.