No one can give you the answers you want.
No one can tell you you did everything you could.
No one can tell you you did everything you possibly could to prevent the outcome you have gotten from your actions. Or that you could have cared less or more than you had time to.
Can anyone say you were neglectful because the normal cleaning and feeding schedule differed from What it was at first? Especially if these were your first bunnies?
Can anyone tell you that you could have been the last thing that your bunny saw or remembered before passing away..?
No.
NO ONE CAN GIVE YOU THE ANSWERS YOU WANT TO HEAR.
It is your choice to blame yourself.
It is your choice to see the signs, or be too caught up in you're own life to see that , what seems to be a small amount of time in between it being happy and it passing away, made a difference.
Only YOU can be the judge of that. But if you choose to fault yourself for not seeing the signs when you didnt know any better, than you will have to live with the guilt.
Or you can say you did everything you could to give them a good life and didnt know how much work they were and made a MISTAKE.
But I feel every soul and every living being has a purpose in this life. And unfortunately, we make mistakes as humans we cant come back from. Unknowingly... we and they, make sacrifices that aren't fair, but happen for a reason. But that is BEING HUMAN. And if they were your first bunnies, then you now know what to look for, and how to differ from past mistakes such as this.
Depending on what breed you get, bunnies can live up to 8-13years. You are their caregiver now. If you thought throwing them into a cage and them being companions would be enough.. then maybe now you will realise that they need YOU. Your love, attention, and for you to care for them when they cant care for themselves. They cant clean their own cage. They cant feed themself, or teach themselves to clean, love, or be there for one another. They cant tell you when something's wrong. They cant let you know that you aren't keeping up with what they need...
It sucks to say.. but sometimes it takes a loss, to be able to fully appreciate the things you may not pay attention to full time In life that you should have.
I'm sorry your bunny passed away. I'm sorry if you feel like you couldn't do anything, or that you could have done more to prevent this outcome. But no one on this forum can tell you the answers you want.
I can tell you to not be so hard on yourself, and to pay closer attention as you move forward.. I can tell you that sometimes they are worse than children and if you dont have time to notice their poops, or their behaviour differing, than maybe you need to take a step back and realise that your life is too busy for something as truly complex as owning a rabbit is..
But it's up to you. You can choose to pay attention. Or you can choose to let **** slip.
I'm sorry your bun has left us. And I hope you chose the right path for where you are in your life. But just remember, the things we want to love us when we need it most.. need it most even when we dont need them.
Goodluck.