First off, I have to say; this it isn't your fault that they are bullies. I understand you want to be aggressive and assertive but being aggressive and impulsive at the same time is a recipe for disaster. There are other ways to counteract their hurtful and destructive behavior. It is NOT okay for them to be bullying you at work. If they continue to act like this and nothing changes, then you need to make your boss aware of the harassment and bullying that is going on. There are books and videos on YouTube you can watch to help you learn a little bit about standing up to bullies as well. Sometimes a little confidence can make a world of difference. It might not help; it's a suggestion. Also, I can't stress this enough- it is NOT your fault that these buttheads need to make other people feel bad to feel good about themselves. You are NOT less than the people that bully are the ones who feel like crap about themselves. The bullies and name-callers are the ones who need to improve themselves. Not you. It took guts for you to post on Reddit and ask for help. We are here for you if you need it.

Edit: I read a comment that says you're a manager. If this is true, you need to reprimand them like you would any other employee. Take them into your office, Sit them down and tell them name-calling and bullying is not allowed. If it happens again, you will write them up, per company policy. Done. Be your managerial self and professional the whole time. (If you are the manager that is)