What you're describing, and please take my words with a grain of salt, sounds closer to burnout than actually hating a character. Sometimes, when I overexpose myself to certain ideas, or characters, or writings, I get so sick and tired of looking at them that I start to dislike them. That's why I think it's so important to take frequent breaks.
Speaking personally, I can't say I've ever written a character I hated that wasn't intentionally supposed to be hated. And even then, I usually take a lot of pride in my dastardly villains. The more reviled they are, the happier I am. It could be you don't feel like your character is serving the purpose you originally designed them for anymore. Again, I'm just offering suggestions. But if that's the case, I would suggest either finding a way to revitilize that character or, failing that, give them an end that's both satisfying and brings closure.