Rabbit disaster

Question
Hello,  I am a proud parent of 4 bunnies (2 lops, 1 Rex and 1 NZ) but up until Monday night was the proud parent of 9 buns.  I housed them in a compartmentalized habitat, built on wood legs kind of like a table.  Monday night I had some family friends over to dinner and was showing off my pride and joy.  The platform shifted and broke, causing the habitat to crash to the floor.  I was sickened. Some of my rabbits screamed during and after the fall.  Two of my buns were hurt immediately (My third lop, Hazal, broke his back and my Mini Rex must have hit his head) and were screaming and making a horrible moaning sound.  Since the gate was open on two of the cages (I was showing off my Flemish, 2 NZs and Netherlands Dwarf) three buns got loose.  My friend's husband, trying to helpful picked up one of my NZs (Jaspar) by the Ears, and then dropped him when he screamed and thrashed.  I'm not sure who did it, but someone accidentally stepped on my ND (Opal).  We never found my Flemish.  Hazal, my Mini Rex, and Jasper were Euthanized on Tuesday, and Opal died outright.  My four remaining buns are eating, but not much, and are no longer tolerating each other or me for that matter.  My lops are still shaking and are in the fright stance, They also scream whenever they hear a loud noise.  Prior to the accident, these were not timid rabbits.  

Are they suffering from greif or PTSD?  What can I do to help them?  I would ask if it would help to adopt new bunnies, but I can't really bring myself to do it.   Can you help?

Answer
Oh my, what a terribly sad week you've had, I can't imagine what you and your rabbits are going through.  My deepest condolences to you.

To answer, your question, your rabbits are indeed showing the rabbit version of PTSD.  

It is very, very good that they are eating some, after such a terrible experience.  Hopefully they'll keep eating and increase their food intake back to normal.  If they stop eating or drinking, it would put them at risk for GI problems, and you don't want to lose anymore of them.

Short term, you've got to find something that will work to help them get their stress level down.   You may already be trying some of these:
1.  When you approach the habitat, do so calmly and slowly.  Try to release any anxiety or stress you may be carrying. Deep, slow breathing may help.
2.  When interacting with your rabbits, always let them see where your hands are.  Move slowly, and softly.  Speak softly.  Don't pick them up unless you need to.  Touch them gently.

Is it possible to temporarily "block off" the sides of the habitat.  To temporarily minimize how much of the suddenly scary world is out there.  In my house rabbits, I'll drape a sheet around the cage when there is a high stress situation.

Another thing to try is giving them some Bach's Rescue Remedy.  I've not used it yet(just ordered some as a matter of fact), but people I know that have used it swear by it's ability to help animals in stressful situations.  It can be found online, and some stores that sell homeopathy products and an occasional drugstore might sell it.

If they keep eating and if there's a way to block off some the scary world for them, I think they'll pull through this.  But it will take some time for them and you.

Hopefully, when their stress levels go down, if any of them were bonded or buddies, they'll find solace and comfort in each other.  They will have to get over the scariness of what happened, but then some may also have to get over the loss of the others.  Particularly if any were close.

As for adopting others, in time you and your rabbits may feel the need to add some new bunnies to your family.  But do so when your heart feels ready and when you think your rabbits are ready.  Doing it too soon, may add new stress for them.

I hope these suggestions help, very best wishes for the future