Is my BTC lost?
Most likely not.
I'd try shutting down the wallet and then starting it back up again
That's not likely to help, but it won't hurt and it's a lot easier than the next thing to try so we might as well get it out of the way in case it does help.
Assuming that doesn't help and that you are running the Bitcoin-Qt wallet, you can try shutting it down and then restarting it with the rescan option.
What operating system are you using? (Windows, Apple OSX, Linux)
If you are not using the Bitcoin-Qt wallet, then what wallet are you using?