You can do more oriented solo things like you were a melee dps without positionnals, and level fine. Fates, battlecraft leves, tribal quests, etc. My tanks have become 70 like that since i didn't 100% like their gameplay at the time and was not interested that much in tanking in a group as well (it did change though with the new DRK that i like way more than the old one). But be warned that it will be way slower than chaining dungeons in a group that will indeed expect you to tank.

And once 71 if you still suffer from "tanxiety" you can use the trust system to try to get more used to group tanking, without the fear of anybody blaming you for your mistakes. Even though it will of course still not be the same if you join a normal group after that (for example when you see how trusts partners are dpsing i dont mass pull with them, but once with normal players most of them will expect you to do that).