Well, first thing first - change your password. If your account has been hijacked, unless your entire computer has been as well, changing the password should do the trick. You can also check your sent box to see if there is any activity that you did not do. And you can always contact Yahoo to see if they have noticed anything unusual on your account.
Christine
Life is not measured by the number of breaths we take, but by the moments that take our breath away.
Cycle! It's Good for the Wattle; it's good for the can!