I'm sorry you are hurting. From someone with a lot of kids - sometimes what kids need is a trusted adult who isn't their parent. Or even a parent. My kids are all fighting for the position of childless aunt or uncle. You don't need to spawn kids for 'being good with kids' to be an asset.
But also as someone with lots of kids - if you want to raise or help kids there are ways to do that even if you don't personally want to reproduce. Half of mine came to me through marriage, and half those my husband adopted from a previous relationship. There is adoption, fostering, Big Brother, Guardian ad Litem, childless people ARE important to children, never doubt it.