I would need much more information to give you a definite answer. Sadly, the at least part of the reason that you aren’t believed now is a result of pretending you were sick when you were younger. It’s a hard lesson in the long term consequences of lying. On the other hand, you were just a kid then. You shouldn’t be held accountable now for something you did 10 years ago.
I’m most concerned about your report that you aren’t sleeping. Yes, that can be a symptom of depression. But it can also be a cause of at least some of what you are feeling. A sleep disorder can have enormous impact on energy, mood, and the ability and willingness to interact with others. Keep a sleep log for a couple of weeks. If you aren’t getting an average of 6 – 9 hours of sleep per night, it’s likely that sleep deprivation is at least part of the problem.
I think your first step should be a talk with your medical doctor. Share what you have told me. Show him or her your sleep log. It is possible that there is a hormonal issue as well as a sleep issue. If so, you need treatment for those issues before deciding that you have a mental health diagnosis.
If your doctor thinks that you do have depression, he or she will also make an appropriate referral to a mental health professional for an evaluation. That will lead to a better conversation between you and your parents.
I wish you well.