First of all, thank you very much for asking a question on AlterHeros. I apologize for the delay it took to answer you. Your question is indeed a confusing subject for most people. I think you’ve started handling your questions quite well by seeking out counseling and exploring relationships and your appearance and dress.
If you do not believe that your gender “confusion” is a phase as you have been told, then you have a few options. If you feel that you want to talk to someone to help you figure out your feelings (gender and sexuality and anything else that relates) then I would recommend finding a therapist who has experience working with clients who are transgender. If you have any desire to “do something” about your gender (for example, transitioning – taking hormones, having surgery, etc), then you probably should also talk to a therapist or psychiatrist. If you feel that you have a firm grasp of your identity, and you do not need to talk to a professional about it, that’s up to you too. You might also want to find youth your age to talk to as sometimes this is more comfortable than talking to a professional. You can either seek out youth groups for LGBTQ+ youth where you live, or find groups online if you wish to remain more anonymous. Additionally, there are a number of books you could read on the topic of (trans)gender. If you live in a city, go to your library and start looking for books. Doing research (be it online or in books) might help you figure things out, or at least start to, and help you feel more confident with your identity. Then, if you go back to a therapist after doing research, and feeling more confident about how you see your identity and gender, they might be more inclined to agree that it’s not a phase. Actually, I recommand that you find a specialist who’s familiar with gender topics since they’ll have the right tools to support you and will have a better understanding of your reality.
As for telling your parents, that is up to you. Some things you need to consider are extreme reactions: if your parents react so negatively that they kick you out, will you be able to support yourself? If the answer is “no,” you might want to wait on telling them. On the other hand, if you know that your parents have friends who are LGBTQ+, or have made comments showing support of LGBTQ+ issues in the news, you might choose to tell them. Again, the decision is yours and I (nor anyone else) can tell you what to do.