Check to see if you have lag, as your game might just be trying to catch up to the server. Try restarting your server, and if that doesn't work, then you could try making a new server. Also, you might have accidentally clicked on an Enchanted Sundial. If that's the case, waiting for 1-2 full Terraria days will stop it.
So to recap in simple steps:
- Check to see if there is lag.
- Wait 1-2 Terraria Days (With a player joined on the server)
- Shutdown and Restart your Server.
- Try a new server. (You could port your old server world to your new one if there is a way to do that.)