Humans are complicated beings and I can assure you, many of us have very complex and complicated feelings toward Carrie and the show. And maybe it’s true what some say — love and hate come from the same place.
As people, we tend to be very passionate about both the things we love and the things we hate. These two terms, love and hate, are two very extreme emotions and we have to admit we invest a lot of ourselves to carry out both (hating things as well as loving things can be very time and energy consuming).
There’s even research about it: Scientists studying the physical nature of hate have found that some of the nervous circuits in the brain responsible for it are the same as those that are used during the feeling of romantic love.
And if you think about it, maybe the hate you describe comes from loving something so much that anything that might endanger it or opposes it must be fought. That’s how hate might be founded in your former love for Carrie, or Quinn, or the show and takes over because you were disappointed and hurt.
That’s only human, I guess, and the question is how to move on from that when you feel it’s getting unhealthy as you say — and I truly believe that hate is indeed a very unhealthy feeling.
A few thoughts: It’s okay to move on. A show which no longer gives you the slightest bit of joy is probably not worth your time anymore. Or to detach and watch differently than before. Or consider to wait some time and to binge then. Or, if fanfic is an option for you, explore different AUs there. You’ll still be with the beloved characters but can warp them just a little bit different and give them a better outcome.
What you shouldn’t do is accept that you are stuck with a show which doesn’t give you anything but negative feelings anymore.