Hi, Sorry this may be a long post.
Lola was bonded to Gus, they were completely In love. At xmas time we went away for a week, leaving the two buns with my sister house sitting (she has 2 bunnies so we were sure of her looking after them). Lola and Gus stayed inside. On xmas night, we had a call to say that Gus had been found deceased on our balcony. We were devastated, especially for Lola. We came home after a week away, and Lola is a completely different bunny. She is aggressive to us, chasing and circling us on movement, and growling (new sound for her!!!). We gave her a couple of days and decided to try to find a bunny to bond her to as she seemed somewhat depressed. We adopted a 12 week old (should have got an adult straight away looking back), and he has been neutered now. We are waiting two more weeks to introduce them on neutral territory (hard as Lola owns the whole house). I am concerned that Lola has been aggressive to us that she may not accept a new bunny now. I have never seen her so bad, at first I thought it may have been grief and she does seem somewhat sad, but this new bunny smell seems to be driving her aggression to peak. I am actually scared of her and have been putting her in an xpen during the day when i’m home 
I feel terrible for her. Firstly, her carer may have been more physical with her (trying to pick her up etc even when asked not to) so I thought that may have been why she was aggressive to us when we arrived home. But since we have acquired Wally, she is even more aggressive.
It is sad for us, as she was such a kind, licking, loving girl before.
Do you think she can accept a new friend or is protecting her territory for Gus still?
Is she just confused?
Will she stop this aggression?
We are desperate. We want our old Lola back.
Thanks, appreciate your input.