Is it normal that i want to beat the living shit out of my gf's cats?

Hey guys. I know the title is a little bit inflammatory, but let me explain my situation: I'm 20 and I absolutely love animals. I have never harmed an animal in my entire life, and I'm actually going to college to become a zoologist. That being said, my girlfriend's two cats make me feel an ungodly desire to beat the living fuck out of them. I moved in with my girlfriend about 4 months ago and everything has been great. The only issue has been her two cats. One of them is about 4 years old, and extremely bipolar. He will rub on your leg and meow at you and roll over on the ground and be extremely cute one minute, and the next minute he will make this nasty ass face and hiss at you like you're the devil. We'll call this cat 'A'. The other one seems to have severe anxiety (almost like he was beaten, but she swears to god that he's never been hurt in his life - and I truly believe that!) and takes weeks to warm up to people. He stays under the bed in our room unless he's shitting or eating, and gets scared at the sound of a pin drop. We'll call this cat 'B'. Now I've owned about 3 cats in my whole life, and I've loved every single one of them to death and would never ever imagine putting my hands on them. However, these cats make me want to strangle the life out of them. This feeling only ever happens around these cats, and only whenever they're being douchey in some way or another. If I go up to Cat A, pet him, and he hisses at me for no reason, I get this overwhelming desire (almost like a 'trigger' out of nowhere) to slap that motherfucker right across the face. The feeling arises in me like a volcano and I have to physically stop myself from tossing that bitch across the room. Cat B has never hurt a fly - he's so sweet once he opens up to you, and I can pet him for hours. For some reason, though, his timidness, fragility, and how scared he is of everything makes me want to chokeslam him into the ground, like the pathetic life form he is. Whenever I'm petting Cat B, I'm just constantly thinking of ways that I could end his existence. I've never felt this way towards an animal, even animals that have intentionally harmed me! The feeling comes over me like anxiety, I can't talk straight when they're by me and I can't even think straight. I've read a bunch of other threads about this and everyone seems to think the OPs are sociopathic/psychopathic and I don't think that's the case. I go to counseling for depression/anxiety and have not brought this up because I feel like my counselor would think I'm a lunatic. I also haven't told my girlfriend about these insane thoughts that come over me when her cats are around. The crazy thing is, my girlfriend and I got a cat of our own, together, about two months ago (Cat C). Cat C is the love of my life, she's perfect, and I love her unconditionally. I have never felt this urge with her. I've never felt this way around my friends' cats, dogs, or anything. Is something wrong with me?!?! I feel absolutely horrible about this feeling because it makes me feel like I'm not fit to be a zoologist, even though this is a very unique situation. Anyone have similar experiences?
Thanks for the input,
-GenuineAnimalLover