The support is going to help. Make sure everyone follows routine, I've noticed things get 'lax' on hand washing and 100% adherence to cross-contamination protocols when mom (me) isn't there to referee.
Get your menu planned, have a few instant meals on hand for baby AND you, assemble your arsenal of substances food and drug that you'll need to survive three days. Pack a hospital bag to include in your emergency action plan for an allergic event. Know where all your epinephrine is, have plenty of freshly opened children's diphenhydramine (Benadryl) on hand complete with known dosage to EVERYONE, reserve some of your oral syringes for Benadryl use. In case.
The hospital bag should have nearly the same items as a hospital bag for birth and delivery. Comfort items, food, OTC drugs for parents and/or child, canister of Neocate or some premeasured doses, extra bottles/nipples, water to mix formula*, small bottle of Clorox wipes, photocopy of insurance card, change for drink machines, phone numbers (you can't always use your cell inside the ER). Include a bottle of Benadryl here and some epinephrine. I've had experiences waiting on a backlogged ER pharmacy to send out emergency meds. They even made mistakes and had to reissue the med. Yeah, that's a great experience. Lesson learned.
The plan is to not need the hospital bag. But when an allergic response starts rearing its ugly head you'll be incredibly relieved to have all that you need on hand.
BUT... I've done days at a time absolutely alone with both my kids. It's doable. The night routine could be rough if your child nurses to sleep. In that case fill his belly with other nutritious stuff then go for a car ride to see of the rumble of the car and carseat is enough to knock him out. Feeding with syringe in the middle of night could be the toughest part but again, been there.
The bright side is you will engineer new survival tactics. Necessity is the mother of invention.
*You don't want to use the sink water to mix formula in the ER. The water from vending machines is also too cold for formula to mix. Clorox wipes are to wipe down extra surfaces since you have NO IDEA what was there before you (superbug?) and the child is so young.