Bless you Hun, Motherhood is wonderful but hard.
Lots of people do W2S for a week, so I would definitely say that it is worth keeping going. Sleeping elsewhere may change things anyway though, so to be honest, I would be tempted to just see what happens when you're at your parents
.
When DS was EW but possibly resettling, I used to split the difference, so if he woke say at 5 am with a possible resettle until 6 am I would take WU as 5.30, so that way I couldn't be too far out WRT to trying to figure his A times, does that make sense
I'm not alone in using this tack
.
Good Luck Hun, hang in there, this too will pass
x.