Changed URL To Add Tracking Code, Account Tanks

Anyone seen this happen?

I have a purely whitehat PPC campaign, I adjusted my landing page urls to incorporate w3roi tracking links, about six hours later the KW impressions shoot way up, cost per click shoots way down to 0.01, clicks still come in, but conversions completely tank. After a day of this, my historic conversions in the XXX range completely drop to 0.

Never seen this happen before, was just curious what others have seen.

Have you confirmed that your tracking links are actually working? If your traffic is still coming in as normal, it's either a problem with your tracking or your merchant.