Sounds like the heads are having trouble accessing a portion of the drive platters. Not surprising if it's the original drive in a 5 year old laptop that's been regularly used since it was new.
I would open up Console.app and monitor it for any read or write-related error messages.
Drives are cheap. < $100 for one twice the size of what you currently have, and most likely faster too. Right now, < $200 for an SSD that's twice the size of what you currently have, thanks to all the Black Friday deals.
... And "no", your drive is not dead yet. If it were, you wouldn't be able to post to the forums at all using it. It does sound like it's starting to fail though.