I agree. That sounds like an awful lot.
I think you should delay the postgrad as much as poss. Or sack it off completely. How far into it are you?
In theory, I'd love to do a PhD. In practice, I won't because I can't afford it financially or for my health.
Hope you can make the phased return work. Have you got a decent HR dept and line manager?
I did my sound bath video at lunchtime. I seem to be keeping my head straight just now at least. Keep on keeping on....