Will this affect my supply?

[Rosie29]

I am planning to leave my breastfed ds on thursday evening and return on friday evening.
I will be expressing to keep up supply, on thurs night, fri morning and again if necessary. Does this sound feasible? He'll happily take a bottle of ebm or formula so it's not him I'm worried about, it's me!

How old is he? How often does he feed? Does he have any solids yet?

He's almost 5 months, feeds around 5 times a day and no solids yet.

That will be absolutely fine at 5 months. In fact the only reason to express is for your own comfort, not to keep up your supply. Enjoy your day off/away - hope you're planning something nice!