She probably knew you really meant a "no" the whole time but hearing you actually finally confirm it upset her because it was building up for so long. I recon she'll be fine, women move on from devastating shit pretty fast.
Whatever she's going through right now will just get worse and worse if she stays with someone who doesn't have the same vision for the future though. So don't let pity make it more fucked up and prolonged.
Also, going by how you described her need for children, if you accidentally get her pregnant and still decide you don't want a kid, you're fucked. She does not sound like the abortion type.