Tilly May, I am not female but I can relate to your sexual preference. I craved other men (secretly - even to myself) for many years, continually denying that I could possibly be gay. I read pornography, watched pornography, read my then-wife's Playgirl Magazines (well, I didn't really "read" them.
Throughout our marriage I fantasized about men but never acted on it. Post-marriage, although I dated other women, my thoughts concerning men were still active. A woman I was dating asked me once, "are you sure you're not gay?" and I'm glad she did, because it gave me time to think. Finally, I reached out to another gay man and had my first taste of gay life. I'm pleased to be able to admit to being gay now and I'm in a wonderful relationship with another man at this time.
Please don't give up on yourself or call yourself names. If you are a lesbian, so be it; and if you need to act on it, I say "just do it."