if you are way off delete your chain and resync
window
go to %appdata%/expanse and delete chaindata
linux
rm -rf ~/.expanse/chaindata
Does that mean my coins are worthless though?
if they are all your blocks then probably.

So I sync then close the genesis.bat then I start expanse and start mining but im alwayjs behind in blocks?
You have to be connected to nodes while your wallet is running, if not, than you are not synced with network.....
Enter "admin.peers" or "net "in console and find out