Did your surgeon say you’d need to keep your head down, or did you read that online? I saw several treatment sites saying the head down post was standard. My surgeon disagreed and said not in my case.
I had a vitrectomy with membrane peel 2 weeks ago. My surgeon did not have to place a “bubble”, so I did not have to keep my head down at all.
Four different eye drops 4x day for the first week and no lifting anything heavier than a gallon of milk for the first 2 weeks. Also, no bending aside from tying shoelaces and no travel by air.
At the 1 week post op, I was doing so well that drops were changed to 3 drops 3 times a day, and to gradually increase activity till I was back to my normal routine by the end of the week. Within days, my vision improved dramatically.
Now, I did have this done about 6 months after confirmed diagnosis of ERM with macular pucker. It was right in the middle of my central vision.
Hopefully your case will go smoothly!

Sleep: you’ll have a patch over your eye for at least the first night. I did use it for the second night, then was fine without.
Can you sleep on your side? I try to sleep on my left side, so as to be kind to my healing right eye.
Suggest you call your surgeon’s office and ask their advice 🙂