I'm really scared. [18+ only]

I've been questioning myself for a good while, and before I was questioning, I never had any doubt when I'd say I want to be a girl. But growing up my biggest exposure to trans stuff or "becoming a girl" stuff was through tg fetish art and I still look at it even now but I've noticed that the only ones that really get me going are things with mental changes, or becoming someone else. But the fact that I become more confident in wanting to be a girl during masturbation is literally torment. I'm not saying that I only wish to be a girl in a sexual context, I wish to be a girl completely outside of sexual contexts too, going to the grocery store, doing hobbies, going to the gym, I'd like to be a cute girl in those too, it's just that sometimes I'm a lot more confident in my want to be a girl during masturbation. This mental torment hurts so fucking bad, and I genuinely want to kill myself over this. I don't want it to just be a fetish, I want to be 110% confident that I want to be a girl, 100% of the time. If it's of any importance, I have unmedicated bipolar depression and I've wished to be a girl while both manic and depressive. Please don't tell me it's just a fetish, please just give me some way to overcome this.

I was on the verge of crying as I wrote the last part saying "Please don't tell me it's just a fetish". I need help, and please tell me I'm not alone in these feelings.