So, you are being followed by a large, black bird. It's very quiet and doesn't seem to want anything with you. Since you haven't died yet, I can assume that it isn't a symbol for death. If it is a raven, then likely scenarios are 1- you are the spawn of Death and he's recognizing you. 2- the raven may believe you are dead and is waiting for you to stop moving so it can devour your flesh. 3- it's a fan of Edgar Allen Poe and is practicing scaring someone for Halloween. Seriously though, even if no supernatural forces are attached to the situation, it's a bird, so what if it's following you. Don't worry about it. What can it possibly do? Creepy, yes, a little, harming, no, not at all.