Hi IDK Anymore, well it's good news that your doctor seems to be taking your problems seriously. And the fact that they've signed you off takes the whole "when you're thinking of returning" to work, out of your hands. Your boss can't really dispute a professionals opinion, no getting away from it, it's a medical fact that you're not ready yet.
Although I'm not sure if the text was meant to put pressure on you in returning, I don't know, you know them fairly well..........???
I'm just thinking it might have been more of a formality in getting an idea around any arrangements they may need to make for your absence or return???
And it does sound kind of friendly.............?? I'm tempted to say too friendly coming from a "professional" , but maybe that's a good thing in the situation????
So yes, you need to give it time till you're ready to return, and just focus on getting the help you need to start feeling better. Work can wait right now, you/your well-being is the most important in all of this.

Alison