the ONLY way your account would be hacked if you GAVE your password out ....
paypal has secure servers so your password CANNOT be intercepted....
you have either clicked a fake email link from "paypal" or actually told someone your password...
log into paypal (if you can) and make your password secure.... IF you can't login then email or ring paypal and they will go through the methods of setting a new password and giving you access back...
and a handy tip ...... if you recieve any email from paypal ......... never ever click a link ... always type
www.paypal.co.uk in your browser window ...... this goes the same for bank emails and ebay...
be safe with your passwords as its your money being used