Is it possible for your AIM to get hacked?

i think my aim account got hacked. one of my friends says she is receiving hateful messages, vulgarity and profane cursing from my AIM account. She is the only one getting them, and the weird thing is I was signed off for the past few days, and she kept getting them, cursing her off and stuff. when I signed back on, she was even blocked from my buddy list. she's the only one getting these messages. what the hell is going on?