How can i become fearless and be feared?

I'm sick of being hurt and pushed around! i don't wanna feel like this anymore, i wanna step up and become someone but i don't know how to, last week i got dumped for someone else and what did i do? nothing! i wanna show people i can be someone in life, i want people to know they cant mess with me and get away with it, how can i be feared? how can i make sure that people will never mess with me again and fear me?