Grey see if your Gp will sign you off work, I got signed off for around 6 weeks initially to get the FBT started and then for another 6 weeks a couple of months down the line when things went backwards for a bit.
Imo it is impossible to do FBT and work as you need to be supervising your dc pretty much 24/7. Each meal and snack can take a long time and when you're not sitting with your child encouraging them to eat you'll be preparing or planning the next meal.
Every single mouthful needs to count, I'm similar to you in that I like a plan and once I worked out the quick way out of this hell hole was to get the weight back on dd, I established a meal plan based on how much double cream I could stuff into everything!!
I added double cream to porridge, soup, scrambled eggs, every single sauce imaginable and at one point we were going through a tub a day.
The good news is this worked in as much as dd regained the weight, her mood improved, the desire to exercise reduced etc.
Recovery from an ED is rarely a straight line though and there are frequent bumps in the road which is normal.
My advice as someone three years down the road is.
Go through your dds phone, check what she's been looking at, check her apps and check her search history. Ideally take her phone off her for a few weeks while you get FBT established. Otherwise put restrictions on the phone so she can't check calorie contents, weight loss tips etc.
Be kind but firm, do not negotiate and do not back down. 'This is what you have to eat, once you've eaten all of that we can watch s film/play a game/ do crafts etc' Repeat this as many times as needed for as long as needed.
Get rid of any scales in the house, insist your dd is blind weighed, ime no good comes of them knowing their weight.
Tackle fear foods early on, if they're going to get upset at least make it count imo.
Do not feel guilty, it's wasted energy and this is not anyone's fault.
Look after yourself, hold onto one or two things you enjoy and find the time to keep doing this.