I made a new TTT server for my gaming community (Gmod), and I wanted to retain our Gametracker rank, so I attempted to change the DNS of our old Gametracker link to the current IP for the new server, and the stats seem to be reset.

Can I get them back?

Can you confirm this was the scenario?

1. Your old page had some DNS set on it and the DNS was pointing to that IP
2. You changed the IP the DNS points to
3. You let GameTracker update the old page with the IP address of the new one

If you have done it another way (ie. backwards), it is possible you could have reset stats since stats are never merged.

Can you provide the link to the new server page and the IP:Port:Query port of the old one?

However, in your question, we are not able to recover stats that are permanently removed.