MAJOR TWITTER PROBLEM?

[Ann]

Okay... So I have a twitter right? Completely normal. But the other day I logged on and I was following all these people I don't know. I never followed them... My brother didn't follow them. So I unfollowed them, the normal thing to do. But then today I got on my twitter and once again. I was following a ton of people I don't know. So I just wanted to know if this has happened to anyone and if they know what's going on. If you know how to fix it... Please please PLEASE tell me! I think I might've gotten hacked... But luckily I am still logged in. WHAT SHOULD I DO???