If at any time you are suspicious of an email, this is what you should do.
First, make sure you are using "full headers," rather than brief headers. In some email accounts, there is a link in the bottom of the right hand corner of the page. Other email accounts, you may find "full headers" listed under "options." Click to use full headers, then look @ the email. Look at the last "received from" source. This is who really sent your email.
Also, a tool to stop these people, and to utilize to really be sure, and also provides a record if charges show up that you didn't make, IMMEDIATELY click on "forward" type abuse@paypal.com (or wherever the email is allegedly from-if its eBay, their report link is spoof@ebay.com ) on the address line. You may include a single sentence such as "I received this email and think it is fraudulent; please advise. Thank you."
Hope this helps GL