Hello Jean. I would visit your healthcare professional. Sometime a general practitioner will be able to refer you to a psychiatrist. Once there at the psychiatrist, describe your symptoms. Don't be too surprised if you are prescribed medication. Take the medication as directed.
As for why you, mother nature is fickle. I too suffer from a mental illness. It can be hell, but it can also be managed. I manage mine with medication, exercise, journaling, and visiting here at Psych Central. I am sure you can find a way to manage yours too. Good luck and hugs.