The gift of knowing how to be happy is very rare. I think I have only ever known one person with this.
In most situations, language can be important-saying you are suffering with your mental health/anxiety/depression (unless, of course, you have a diagnosed mental illness) can make you feel worse-it just sounds so...overwhelming.
I think for most of us, most of the time, we simply have a case of the blues and it will eventually pass.
Mental health has become a fashionable phrase and it seems to focus on the opposite of what it actually says-people seem to use it to mean they have problem with their mental health.
Most of us do not have problems with our mental health but, as part of being human, we sometimes feel miserable, unhappy, upset or blue. It's part of life but , for most of us, they are passing feelings or a reaction to a temporary situation. It's not a medical situation.