How do you know when you are/if you were a bully?

When I was in high school middle school kids always had an attitude and I didn't hesitates to get physical, especially since I knew the bus driver didn't care (the high school and middle school are next to each other so they use the same busses), now that im done with high I don't do that anymore, but high school made me become mental (I do get help for my mental issues such as depression, anxiety, mood swings, and cutting), and if somebody annoyed me these days I would probably just use my psycho laugh and look scary (which I've become good at since I've gone mental). Was I a bully?