KellBelle,
There is no one so far that can look at you, or ask questions and based on those results say you are not a girl. They can guess, suspect, allude and conclude. However, this is something that it is really for the person experiencing it to realize. There can be roadblocks from psychological, medical, familial or societal members. However, if this is what you are, they can't see inside your mind. At this point, it may be easier to say "I'm not a girl". Sooner or later, it will come back if you are transsexual.
If you are not. Try to not go in that direction. You have already suggested that this will depress you. I don't know that it is dysphoria that makes you think you are not a girl or even makes you sad when you think that. It is conflicting thoughts and feelings at battle with each other(that may be dysyphoric). That is where the therapist I suggested in another post helps. Not to tell you what to do but to help you find a way to your own truth through these conflicting things going on within.
Not sure I can help you with much more. I can suggest you look for the good in whatever you can (people and situations). I can suggest you see a therapist and work through this. I can suggest you try to distract yourself when you get in one of these moods. But I can't and shouldn't force you to do any of these things. Goodness knows, I am in a very dark place myself right now. Perhaps it is because it is not about me that I can look at your cries for help in a more objective way than I can look at myself.
Look at doing something. Reading, riding a bike, watching a video. Bide your time till this mood passes or you come to grips with it. I hope your day and week gets better now.
With warm thoughts,
Joanna