I am having a similar problem, including an anxiety attack.
First, you'll need to calm down. Trying to address the situation while in the midst of an anxiety attack is a sure way to make a mistake, make things worse, and lose your bitcoins permanently.
Right now, assuming you haven't started messing around with deleting, re-installing, or moving your wallet yet, your bitcoins are almost certainly safe. You can't see them because the wallet youa re using hasn't caught up with the blockchain yet, but they are probably still accessible.
If you know the bitcoin address that you expect to receive the bitcoins at, you can use the following link to see that they are fine. Just replace the YOUR_BITCOIN_ADDRESS_HERE with the bitcoin address where you expect to receive the bitcoins:
https://blockchain.info/address/YOUR_BITCOIN_ADDRESS_HEREIf the bitcoin address that you expect to receive the bitcoins at is displayed in the "Receive Coins" tab of your wallet, then you almost certainly have the private key necessary to access those bitcoins.
Depending on how far behind your client is, it can take a long time to catch up with the synchronizing. If this is a problem for you, you may want to consider accessing your bitcoins from a "lightweight" client such as Electrum or MultiBit, or even consider a web hosted wallet such as
https://blockchain.info/walletIt would be a good idea to make at least one backup of your wallet.dat file, just in case you mess things up accidentally while trying to solve your current issue. The more recent versions of Bitcoin-Qt all have a menu option to "Backup Wallet". That is probably the safest way to do it if you aren't comfortable moving files around by hand.
If you are sure you know what you are doing, you can also find the wallet.dat file on your computer and make a copy of it. This is the only file you need to be able to recover your bitcoins.
If you want to use one of the lightweight wallets or the web hosted wallet, just say so, and I'll provide you instructions on how to get your bitcoins imported into the wallet you choose.
If you only want to use the Bitcoin-Qt reference client, and you are certain that it isn't downloading any blocks any longer, then just say so, and we'll see if we can get it restarted for you.