How to confront someone who's talking behind your back or has done you wrong?

[Rain]

I usually just go up to them and say "Hey, *insert name here*!" and I say yeah a lot and act offended of laugh and smirk the whole time and say things like "If you do it again you'll be sorry" sometimes "You're not doing that again". And I insist that they won't, when they ask why I tell them "Do it again and find out" and I walk away laughing. Sometimes when they have good comebacks though I get sort of watery eyed. I can't help it. I get offended easily, I take a lot of things personally. I hate emotions as well... I try to remind myself that words are empty but it's hard. And I don't have good comebacks, I can't think quick and I don't like hesitating, it makes me look stupid, some of the things I come up with on the spot make me sound stupid too though. People have a tendency to think that they're better than me, but the moment my sister walks in I'm equal or superior, they gang up on me with their friends, I hate it.

I think it would be a lot easier to pretend to be someone else, someone tougher with more confidence while I'm doing it but it's hard. Would anyone mind helping me out with this?
When I do keep up a hard front while confronting someone, I find it hard to keep up with the mask. I'm always joking around and stuff with my friends (who aren't the most popular people ever, not even close) and I wear colourful clothes and I'm really sensitive sometimes, though I have a tendency to look serious a lot and act insensitive to people I don't know and avoid confrontation with people who talk about me or make comments about me. If I hear it I look at them and look away, or sometimes don't look at all and pretend I don't hear it. I've been bullied all my life and have always attracted the wrong people.
Strawberry: I like it better to confront people around others. Is that why this happens? I should just pull them aside and say it? I thought they would have less a chance of lying or being a jerk in front of an audience. Was I wrong?

[StrawberryCrispii]

If they are talking crap. Ignore. Its not even worth it. It means they are below you and you are ABOVE them. Now, if they are spreading rumors, that isnt so nice.. you should probably go over and have a little talk with them.. like whatsup and why are you spreading rumors? I bet you fight with your siblings or mom sometimes right? You're not like shy around them or seem stupid.. You say whats on your mind! Because u can be angry at whatever it is... and you can hurt them sometimes and you realize it.. so why can't you use the same power and hurt those people that are hurting you!? that actually deserve for you to be angry at them.. don't be scared.. they are scared as well.. thats why people hide behind computers and social media to talk crap.. cause nobody can hurt them there.. true story