Hello from last 2 days am getting my BTC wallet error when i try to send payment to anyone the error pop up " prev out is already spent "

Why i`m getting this problem?....please anyone can help me?.....
How i can recover my BTC now?
Please kindly help me if anyone can.....
Blockchain.info wallets has two wallets and addresses being showed at the same time. So it is possible that you already sent your bitcoin to another address but you used the other wallet and so there are no items appearing on the transactions. But if you try to select the other wallet it will allow you to see the transctions made by that wallet. I also have experience the same and I realized later on that it was due to the new feature of blockchain.info wallets.