My Horse :(

I'm really worried, my horse is in really bad shape, she can't walk...Or, i guess, she can walk three steps and then she can't move...And if you pick up one of her back legs than she falls down. The two possible things she might have are just a pinched nerve, which i'm praying is all that it is, or this disease which is going to leave her unridable forever or at least for a few years. I know that at least she's not going to, i don't even want to say the word, fill in the blank for yourself, but still, i just hope to god that it's just a pinched nerve. And if she's going to have to suffer we'll put her down. I just can't bear the thought of losing her, she's my best friend, she's the best listener ever and i know that she's just a horse but i love her more than anything. we've already lost one horse to drowning and we had to put my dog down not too long ago, i can't lose another one. Especially not her.