What is wrong with my mouse?

I went to bed last night, everything was perfectly fine, I wake up and all of a sudden my mouse is acting weird? It's the most annoying thing - my right click acts like left click SOMETIMES, so I can never predict when it'll suddenly act like the left click. Once it does it goes on a spree of acting like a right click for the next 5-10 clicks then it'll stop. 

I don't understand how or why this happened, I have an alienware mouse and it's barely 6 months old. It suddenly, randomly and inconveniently started acting up. It makes it so I can no longer copy + paste, play games that rely on movement of the screen by right click, sports games, etc. because the right click keeps acting like a left click and doing whatever the left click does. (For example, in Call of Duty, I'll be aiming with right click and all of a sudden it'll start shooting the gun which the left click does.)

Please help... I have no idea how this happened and it's EXTREMELY inconvenient considering the amount of work and study I do on this expensive computer.