You're doing an amazing job to manage this so soon, my biggest advice would be to be kind to yourself and prioritise what makes you most calm and confident with the new routine. It might mean a few experiments, but you'll get there.
For me, the best advice I found on early returns was on US sites, as so few women in the UK have experienced these challenges. Kellymom is good - also if you are in the UK, la leche league has some advice and many areas have a local lactation consultant you can speak with.
Things that helped me-
***Rent or buy a hospital grade pump where you can run both sides at once and a double pumping bra. The difference is ASTONISHING
*Being really routine driven about pumping when back at work
*While pumping, sounds silly but my output was much higher when I did it while listening to music I love and doing something about my babies - looking back at photos, sometimes choosing nice ones to send to family, wish I'd used the time to note things down as you forget so much
*Make sure that the caregiver when you're away is using a slow flow teat and also finding ways to soothe them other than feeding - eg slings, cuddles, songs, walks in the buggy etc. Sometimes feeding can be a simple way to settle them, but over feeding by bottle is bad for your baby as well as your milk stash.
*People here sometimes catastrophise about any formula use being a gateway to end of bfing. It's not true - sometimes it is in the UK, but that's because we have one of the lowest rates of bfing in the world, so there's much more tendency to drop it anyway. In many other countries mixed feeding is a norm. For one of my babies I had to stop breastfeeding for 2 weeks completely at 3 months old due to emergency medical treatment, and still managed to re-establish full breastfeeding.
**On your specific idea.
Are you pumping at all on your work days?
If you are, then there might be a one off formula day while you catch up and some occasional supplementation, but couldn't you use that milk to be the feed for the next week's work days etc?
If you're not pumping for full days or even half days while working, then you're very likely to find your supply will drop on your other days too. Unfortunately there's no legal right to express milk in the UK, but most med-large employers have a policy that will allow it, and that promises somewhere to store milk etc
Personally I'd not drop a feed at home in order to express - you'll likely produce less and your baby will enjoy it less, just leave the formula for the days you're at work and don't have quite enough.
One thing that can work well, especially if you can get the double pump, is at the end of a few feeds when your baby is feeling full and the logistics work, hitch the pump on and try for 5 more mins or so. A bit annoying for the sterilising etc (though I relied on the dishwasher and then microwave so wasn't too bad), but it's a fairly easy way to build up a surprising amount more without risking too much of your current supply.
However, if it's what you definitely want, you should try - again, your baby is going to be ok either way, the important thing is to keep you both feeling ok and enjoying these early months as much as possible.