Replying to How to be mean/not be a pussy?

NS, I'm really fucking soft and I don't know how to stand up for myself. I always feel guilty when I have to say no to someone and I just don't know how to not give a fuck. I go too far out of my way to help people and I've been getting really fucked over because of it. I'm pretty sick of it but I seriously don't know how to be mean. I just love everyone and want them to like me, so I try to be as nice as possible even if that means I can't do something I need/want to. The best insult I can come up with is fuck you, you're a bitch. And even then I feel awful after. How do I stop being such a pussy and push over?

I figured most of you guys don't give a fuck about much, I wanna be like that. How do you guys not be pussies?