Simply opening an attachment on a dodgy email can be enough to dump malware onto your computer. (I can't think of any reason why Apple would need to include an attachment if they genuinely wanted to let you know about suspicious activity on your account). Run a full virus check, and a anti-malware check, straight away.
If you get an email (which is apparently from eBay, PayPal, Amazon, Apple, your bank or whoever) which tells you that you need to log into your account, you should NEVER do so via a link in the email. You should ALWAYS go direct to the relevant website and log in from there.