If Harlow was with any males 6months or older then its very likely this is real pregnancy. It’s so unfortunate you’re having to deal with someone else’s actions. I’m sorry for that. Be assured you’ll get support here.
This article from HRS is full of helpful info.
http://rabbit.org/domestic-baby-bunnies-and-their-mom/
Assuming this is the real deal, give Harlow unlimited food and make sure she has somewhere to go away from the babies. They don’t stay with them but only visit briefly for nursing.
If possible, check in on her while birthing. You might think she’s all done and she leaves the nest, only to return a little while later to birth another kit.
I dealt with this early last year with my rabbit Maple. She lost 3 of the kits as they were 2 big. The last she had 30 minutes after the others and this one became stuck. I had to help in the end because she became distressed. So im thankful i was there but not thankful she was pregnant in the first place. Being a dwarf, she did have difficulty.
If you are there, youll see she’ll eat the afterbirth (I think each time??). This can be where mishaps occur if the accidently bite part of the kit. Especially with young mothers. You may have the chance to safely move the kit and settle it in the nest.