The best way of verifiying if the mail is fake is to check the mail's headers.
In G-Mail you can check the sender using the little arrow as you can see here
https://gyazo.com/06316ecfb1393b81e9b5341013ac01aeThen you should get the message headers as you can see here
https://support.google.com/mail/answer/22454?hl=enThose can get copy & pasted here
http://mxtoolbox.com/EmailHeaders.aspxIf the mail is fake, the result will mostly look similar to this
https://gyazo.com/14bcf794bd61394e155eb2df299d17c7, containing links which are not associated with PayPal.
To compare, a valid mail from PayPal
https://gyazo.com/3b0bde78a6fe709c99febb2d0180c4cd |
https://gyazo.com/92135cddb5a3388b1db9208bced163a0.
Additionally Google will tell you if three tests (SPF, DKIM and DMARC) are passed, see
https://gyazo.com/4861933bd86881a86a46a7e8d7828990.
And like
Spoetnik already told, PayPal should show you a notification if you login at their site (Not use any link of a mail, go directly to PayPal or use Google).
Friendly Regards,
- SkycityVictorians