Is it normal to have extremely violent sexual fantasies?

I absolutely HATE violence, I could never hurt a fly, and actually I like being submissive to girls in general. However, I keep having an extremely disturbing violent sexual fantasy involving raping and murdering a ten-year-old relative of mine (by marriage, not by blood). In the fantasy, I tear her clothes off, throw her on a bed, and cover her mouth as I rape her from behind (vaginally). Then I take her stockings (I have a foot fetish) and lightly strangle her with them as I rape her in the missionary position. Just as I orgasm, I break her neck by pushing down on it as hard as I can with my arm. As she chokes to death, I hit her repeatedly in the head as I hard as I can and yell at her (things like "slut", "shut the fuck up", "you stupid fucking cunt").

My sexuality is really, really fucked up. In my early childhood years, I was obsessed with "playing doctor" with anyone I could (boys and girls). I was molested when I was eight by a friend of the same age, but I didn't really see it as molestation until recently. I've had a really bad foot fetish since the age of 13, and I've been into BDSM since age 14. I repressed my bisexuality for years because I live in a bigoted, homophobic hick town.

I'm really, really worried about this shit. I feel like I've become a monster, but I would never, EVER do anything like this and I hate myself because I can't stop thinking about it. Should I go to a psychologist or something?