If you opened your IOTA wallet in the last two days and you are new to IOTA, then you probably were a bit shocked seeing that your balance was 0. You might even think you got robbed given that IOTA seed theft from which happened to some who used a website to generate their IOTA seed. If started sweating, you can now calm down.
Have a look at your transaction history. If you history shows no entries, everything is okay. Nothing to worry about. If it shows that you have sent all your IOTA to another person, then the bad news is: you just lost your funds. Next time generate a secure seed and start over. But if the history is empty, all you need to do to re-claim your funds is to generate a new address and attach it to the tangle.
Just generate new addresses using your seed and attach them to the tangle until your wallet shows you the correct balance.
I hope this little guide helps you and next time, don't get stressed. Have a look at your transaction history first. And make sure to never use online generators to generate private keys or seeds - you never know if they get stored somewhere for fraudulent use.