Oh my gosh, I'm so sorry. That is really very very hard! I can just sense the heartbreak you feel in your words. I had to place a bunny for adoption once. My heart was broken, not to mention, no matter how nice the rescue people are, I still felt like they were condemning me in their heads. I owned a house with my fiance, and we had just gotten a yorkie puppy. I had the bunny, which I rescued from a shelter only a month prior. The bunny and puppy were doing so well together I would find them laying side by side on the couch together all the time, sooo cute.
One day my fiance pretty much came home and told me he didn't want to get married and he didn't want the pets, I could have them. Well I kicked him out of the house, so suddenly I was taking care of the house alone, the 2 pets alone, working full time and going to night school. (my ex was home a lot since he was a Firefighter and worked 2, 24 hour shifts a week, he was home 5 days a week). Plus I had to pack up the house, sell it, move, cancel my wedding, and deal with a broken heart (we were together 10 years) ... I just couldn't do it all and my pup was only 5 months old. So with a heavy heart I gave up my bunny to a rescue locally. It was the best thing I could do for her at that point in my life and hers. My mom helped me with my puppy, often taking him overnight until his sudden unexpected passing. 5 years later, I got the opportunity to rescue another bunny and I did! She passed this summer, but she was with me until the end and very well taken care of! She died a happy bunny at least!

I paid it forward, and I will do it again!
(((HUGS))) to you!