I'm so sorry! Know that she was blessed with having you and that you made her life good. It's so hard to lose our friends. I know it's cliche but time really does heal up the wounds and you're never put through what you can't handle. I've lost many pets and it gets easier. They bless our lives for a short while and make our lives all the better.
If you still can I'd cut a good chunk of her tail hairs off and braid a keepsake for yourself. I sent my gelding's tail hairs to a lady who made a horse hair pot from it and braided the leftover hair around the lip of the pot. You can choose the color beads so I chose my show colors. I think it helps to have something that was there's to help remember them by.
Very sorry for your loss. *big hugs* I wish there was something I could do to take the pain away. You just have to love them all you can for as long as you have them because you just never know. I truly believe everything happens for a reason even if right now you can't see what that reason is.