I have noticed that some of the new pictures that come just somehow add to my favorites even if i havent been here? Does this happen to anyone else. Maybe someone using my account or something i dont know

Are you sure you're looking at this page? If they are showing up there, then try changing your password.

Maybe you favorited posts that weren't the full resolution and got re-uploaded by someone. If that's the case, your favorite on the old post will be transferred to the new one.