I sent a transaction with bitcoin core 0.14.2 and I noticed some coin missing. The amount in my wallet shows as correct but on blockchain.info I can see 2 amounts where sent to different addresses at the same time. I'm really concerned the pc I was using is compromised in some way. Help would be appreciated.
Bitcoin core wallet contains more than one address. For security and privacy reasons, when you make a transaction, the change returns into another address of yours.
(This is why regular backups of wallet.dat are a good idea.)
However, there's nothing to worry about, especially as the wallet reports the expected amount.