I really don't think it was hacked from psn.
Or did you buy something while using this psn ? :
https://store.sonyentertainmentnetwork.com/#!/fr-fr/home/main
If you had a specific virus at the time, then yeah, your information could be stolen by someone else...that's what hapenned to me once, because i wasn't cautious enough.
(and because i didn't take any precaution...uhuhu)