I'm crying. I don't know what to do

Okay so long story short, I'm crying my eyes out. My mum seems to think that rabbits are some sort of toy that toy can throw away when you get bored of.

Both of my brothers don't care about my bunnies. I love them to pieces though. Because my brothers don't care, my mum's getting rid of them. I ****ing love them though. They're the first pets I've ever had, and I haven't even had them for 2 months. I clean their cage every week and do just about everything for them. I actually ****ing love these rabbits. I don't want them to go. Part of me is saying "they'll go to a better home, and they might actually be allowed indoors when winter comes", but another part of me is saying "But they're MINE." They're my pets and I love them like somebody would love a puppy, I don't know what I'm gonna do. I don't even know if help is possible, but I'm crying as if my best friend's just died.

My mum's giving them away tomorrow and I'm already feeling depressed.

How old are you? Who is paying for the bunnies expense and what is your mum's reason for rehoming them? Seriously, no offense to your mum, but I hate adults who abandon animals for no reason, teaching their children that it's OK to just get rid of animals whenever they want. Don't you have a friend or a family member who could possibly keep them for you? Tomorrow is really short notice too. I understand why it feels unfair and terrible to you. The problem is 'your parents house / their rules'. Still, I don't think it's right for them to agree to take in an animal and then change their mind without any major reason - when you take an animal home, you are honor bound to take care of them the best you can until they die or unforseen circumstances make it impossible for you to do so.
If there is nothing you can do to change her mind, I would do a very complete care sheet about your rabbits to give the adopter and have a talk with them when they come to pick them up to explain that those rabbits are very important to you. Give them your email adress and ask if you can have theirs to ask for news and photos from time to time. It won't be the same, but if they were mine I think it would help. Most people aren't monsters and they'll probably agree - I still send photos and news of my animals to their original breeders from time to time!
Also, I wouldn't take another pet until you can live on your own as an adult to avoid a repeat. Take it as an opportunity to research which animal you will adopt next and how to take care of them (my parents hate dogs, I have waited and researched for all my teenage years dreaming to get one - going to a breeder to chose a puppy was the first thing I did when I moved out ^^).