I urge you to seek professional help to answer some of your questions.
The question of whether or not it will persist has to do with those factors including your family history, how many relatives have struggled with depressive symptoms with no apparent environmental cause and how much this has happened in your life before. A mental health professional will take a history to help determine to what extent this is situational. Whether it is an ongoing clinical depression or not, there is always hope. If it is a clinical depression, there is always help best with a combination of medication and therapy. I've seen many people do well with just medication and some do well with just therapy. But keep in mind that the therapy needs to focus on specific tasks and skills that help to alleviate the symptoms, while the medication has to be manageable by your body. There is always hope.
Your concern about your symptoms and mood show an awareness that is commendable. Not knowing your background nor history of your symptoms it would be inadvisable for me to speculate. I would suggest you find a licensed Mental Health Professional like a licensed Psychologist or a licensed Clinical social worker to address your concerns regarding your symptoms and gloomy feeling. Upon evaluating you, they would be better able to answer these pertinent questions.
You have to act counter to the lie. You may have to risk taking chances, since taking chances has its pay offs as well as risks. You may have to risk giving your heart away even if there are no guarantees (and work on the traits you have developed that could push someone away). You may have to risk going for broke to achieve something, so you can see you are not worthless. You may have to give up criticizing or controlling others so that you don't worry so much that they judge you.
Depression is only permanent if it goes untreated, and I do not mean medication.