Is this normal or a sign of hysteria?

Every once and awhile something triggers me to laugh hysterically. Like the thing I am laughing about isn't even funny, and I just start laughing...and can't stop. It has gotten to the point that when I do that, my family and friends yell at me to stop because it scares them. I am not anxious or anything at the time that I laugh like this, it just happens. After the whole "episode" finally stops, I feel sad and upset because my family and/or friends are annoyed or worried about me. Is there something wrong with me?