My Yahoo Messenger ID was hacked!!!

Yesterday, I was trying to log in to my yahoo messenger account and I wasn't able to. Then I tried checking my yahoo email ad and I got a message saying that my ID has been compromised. I had to change to password and all that. Maybe this is the reason why my cousins and friends are asking me if I am using Acai Berry because they received numerous messages from me saying that I lost weight because of Acai Berry wherein in the first place, I don't even know the color of Acai Berry. I just hope that this won't happen again. I hope we can do something to prevent this from happening again.