Jenn, l know exactly how you feel, l had the same experience
We took a rabbit in from the neighbours, who neglected her our Emily that is. We decided to get another rabbit to keep her company, we bought another hutch so they could get to know one another, we kept the hutches facing each other for a while, apparently lf you put a rabbit in the same hutch as another, you have problems, a bit like territorial ground and they fight.
Anyway Emily and cruella (my 3yr old grandson named her that) got on great for about 18months, then Emily started to get frisky and would not let Cruella alone, she was always on her the whole time.
One day l went to feed them and found poor Cruella dead
l did not have a post mortem on her, but when l spoke to the vet, he said(she most probably died of a broken spine) there was no other reason
She was full of life the night before.
We still have Emily would you believe she is now 10yrs old.
We never got another bunny to keep her company.
Just an experience l wanted to share with you, and know full well how you feel.
Doreen.