Have you thought about the possibility that you might be somewhere under the nonbinary umbrella? I was in the nb community for around 2 years, and there are a ton of different experiences there. You may want to look into the term "genderfluid".
Either way, I understand your feeling. I went back, and forth, and back, and forth with genders for around 2 years. Went to get HRT, canceled, went to get HRT, canceled, etc.
I never thought I was supposed to be a boy up until recently, and using the term "born in the wrong body" is a new thing for me. When I first realized I was trans, I didn't have the words for it, given that I was 12. All I knew was that I was, what I now know to be, dysphoric. However, my dysphoria waxed and waned for a long time. Still does a bit, actually.
I understand not knowing your gender. For me, I never doubted if I was trans, but I DID change my gender identity every 5 seconds... And even now, I'm a bit of an "odd" FTM, in that I still enjoy makeup and feminine fashion.
And on your second question, I've had many-a-night where I was purely distressed by the fact that I am trans. I've often wished I wasn't, sometimes I wish I could've just been a cis girl, that I could've just...continued on, unaware. But I think it's a matter of accepting that that's not who you are, and trudging on, you know?
Basically what I'm saying is, you may be trans, you may not be, only you can determine that. However, I think it's important to remember that trans experiences come in every shape, size, form, and color. You are not alone - you may have just not found your tribe yet, so to speak.
Good luck.