I think it's wonderful that you're able to be so honest about this. And even better that you say you don't want to feel that way. Someone once said to me that if I was worried about being a good mother (which I did and do, constantly) I should be aware that the very fact of worrying proved I wasn't as bad a parent as I feared. I suspect this is true for you.
I love my children very fiercely, but I have to say I don't really miss them when we're apart. As long as I know they're safe and having fun without me, I don't have a constant urge to contact them or a longing to see photos or get updates from whoever they are with. I never have. I don't think you can use that as a measure of your feelings, so I'd push that to the bottom of the worry list.
Finally, I wanted to say that I have always found it really difficult to relate to one of my 3 children. We just don't "click" and never did, even in their babyhood. I don't love them less but I found spending time with them harder than with either of the other two.
What helped me there was when they got a bit older and I just relaxed into myself, without trying to parent them, just treating them as my adult equal. One day my kid said with amazement "you know, you're really genuinely funny!" and I realised that I share a sense of humour with them, way more than with the other two. I'm sharing this so that you know it's never too late to discover common ground from which a relationship can develop. My child was in their late teens when we discovered we like and get each other's humour and our relationship has developed exponentially from then - which is in total contradiction to my fear, which is that they would go off to uni and I'd never have bonded fully with them.
I think you should certainly speak to someone about your own experience of being parented (as lots of people have said) I know for myself that I found so many unexpected answers to all sorts of life questions when I looked into my childhood with a therapist. But above and beyond that, maybe relax and stop beating yourself up quite as much, because love won't grow while you're worried you're not good enough for it.