You are not heartless for not feeling grief over your loss. Everyone deals with it in their own way. My husband just said it will be OK. And that was it. Then about a year later a friend of his at work had asked him to borrow 700$ to pay for his wife's d&c. He told me he was only going to lend him the money because he remembered how helpless he felt when we had "our" miscarriage. I wanted to cry because there I was thinking he didn't care and he did. We all grieve differently. No one can tell you how to react. I'm sorry for your loss and i hope you get your little miracle soon! Baby dust to you all!
I have a friend who still feels like that, years later, because the man who she got pregnant by was being a complete a*hole. But there are several stages of grief, and I suspect you're just in the first one, where feeling like that is normal, and it'll hit you later. I lost my brother over 15 years ago, and at first it felt almost unreal and I rarely cried, just felt kinda numb...the feeling came later, and boy did it come. But however you feel is perfectly normal, there's no "right" way to go through something like a miscarriage.