Dogmeat disappeared on me after Take It Back.

I may have messed up by telling him to go and wait for me at Vault 101 just before I activated the GECK, instead of the Goodbye dialogue option.
I went looking for him after waking up and he was not at Vault 101, not at the Scrapyard, I ran from Megaton to the Jefferson Memorial to see if he was still on the road, he wasn't inside the Jefferson Memorial either.

I know how to get him back via the console, but can anyone explain what went wrong?

It could take him several days to get back to Vault 101. Followers take long confusing routes to get back to their default locations. I fired Star Paladin Cross at Underworld and it took her over six game months to make it to the Citadel.

Wow! that's insane... six months.

I just assumed that because you're technically asleep for two weeks that Dogmeat would have had more than enough time to make it back to base. Perhaps he's gone to Raven Rock to admire the ruins first.

Yay, Dogmeat turned up at the Scrapyard after 3 weeks! Stupid canine obviously doesn't understand English! I clearly said 101...
Still :celebration: my bestest friend is back!