I am the same way...can't bear to hurt an animal (unless it's a spider...those bastards are on my radar!). I've had many pets, some were considered unconventional (I love rats), and some were of the more normal type (cats, dogs, hamsters).
OZ~ You mentioned the mouse you tried nursing back to health...I've got a story for you! I used to work in a warehouse and the company owner used glue traps (I HATE THOSE THINGS! SO INHUMANE!). Well, one morning while I was filling a product order, I smelled that "death" stench coming from the corner where the water heater was. I went to look, and lo and behold, there were 2 tiny field mice on it, probably only a few weeks old and JUST venturing out of the nest. I immediately felt a little stab in my heart at such a loss of life...but as I was looking, I saw one of them start squirming! I knew I couldn't just leave her there to die like her sibling...a glue trap death is long and painful...they basically struggle until they rupture internally and bleed to death. I couldn't allow that! So, I picked up the trap and headed to the bathroom with it (my co-workers looked at me like I'd lost my mind). I ran the warm water and applied it to the edges of her fur (she was stuck on her left side, so half her face and mouth, and 2 of her legs were glued down). I slowly and painstakingly applied water and kept prying little by little, gently, until she finally came free! Poor little thing had been stuck there so long, her entire side was paralyzed! She couldn't move it at all. I got an empty candy container (plastic) and put a mound of toilet paper inside, and then I put her in it and put her in the break room. On my lunch break, I shared my string cheese stick with her, but she was so weak and couldn't move her jaw enough to bite it, so I scraped bits of it onto her incisors and she used her tongue to move it to her back teeth and chewed as best she could...I also used a small bottle cap to give her water bit by bit. I brought her home (and named her Sticky) and I fed her like that until the next afternoon...I went to feed her again, and she was GONE! I ended up finding her in the bathroom and caught her (she was a fast little bugger!). At that point I realized she was just fine so I let her go in the grass outside. She squeaked a little when I let her go, and I liked to think she was saying "Thank you".
Oh! Speaking of rabbits, too... There are bunch of them that hippity hop around here late at night and in the morning... The night before Easter, my dad and I were coming home and we saw one running on the side of the road... My dad says "Awww, bun-bun!"... I said "Yeah, the little bastard's out hiding his eggs!!" He almost drove off the road laughing...