I got caught working on personal projects during work hours yikes! But hear me out
Im a graphic designer for a digital marketing agency and i run my own art business on the side. So on my day to day i have a few tasks that i need to accomplish plus all the other stuff that my coworkers request from me. That is my role, they need it, i design it, they post it. 

Im fast and efficient, usually work very quickly and i finish my daily tasks ahead of time on most days. Some days are more hectic and some are super slow. So when i complete what i need to do for they day, or have a few hours to kill,instead of dicking around online on facebook or shopping like everyone else in the office i use my free time to work on my side projects.

My boss finally saw what i was doing yesterday when i got up to go to the bathroom and i left my screen on whoops. there had never been any complaints about me before but now they got me on a tight leash and threatened to reprimand me economically if i don’t stop doing it. I got a very menacing email threatening to fire me :/

So my question is, is what i am doing wrong even if I still preform my job effectively and on time?