I just told my girlfriend I love her but now I'm thinking of leaving her.
Why would you be cruel to your girlfriend?
I'm too attached to her, and I cannot do this to myself anymore, I would rather leave than continue on with such feelings.
It is wrong to leave your gf if you tell her you love her. Talk to her and work out your feelings.
Why is it wrong? If I want to leave, I should just leave.
I get that you want to just leave and end the relationship, but you just told her you love her. You drew her even further into commitment and now you want to back out which is really cruel. You should try working out why you feel this way all of a sudden rather than just abandoning her.