After crying for several days straight, I was convinced something was wrong with Seamus.
I gave him a good look over and then decided to let the vet take a look.
After a $300 visit to the vet (UGH), it seems Seamus was sick of two things:
The hot weather & D being away.
HERE, HERE, Seamy!
(Except, next time, maybe you could not cost me $300 for that message? Ok. Thanks buddy.)