I think this is just the normal fluctuation during the dance. I've seen home pages on good sites show a PR-blank a few times today. Keep checking and see if it sticks. My guess is that it won't but I'm not positive about that.
During the update, things jump all over the place for several days. If your PR was 5 before the update, it may lower to 0 during the update, then rocket back up to 6 after the update finishes. Noone knows for sure what's going to happen.
Just wait a few days (until the dust settles) and then worry about the results.
In addition I only link to the add resources page from my resources list page (PR5) what would happen if I put a link to it (i.e. Link To Us) on each page? Would it make a difference or if it is penalised... will that in turn damage each page linking to it?