Why is it im scared to stand up for myself or scared of confrontation?

like the life guard at the swimming centre who walks around like a tough guy and who i feel stares at me, its detered me enough to stop going to the gym for two weeks. but one thing i can say and that i think might be one of the causes of my terrible anxiety and panic, im scared of losing control and becoming aggressive through my rage i struggle with. i think its the consequences of what could happen, gettin in trouble with police and gettin arrested etc, because a while back through my anger, i got in trouble and kicked someone for no reason, i ended up in a mental hospital, im ashamed of this & tryin to put this behind me. but ever since this memory hangs over me like a threat of what could happen if i lose control of my rage. if gotta say id rather be dead than be incarcerated again, & if i knew i was going to be, i would terminate myself rather than face that. but i dont wanna always live my life scared & frightened to stand my ground and face life, but i cant do it at the moment