I think you're being so patient and really doing a fabulous job. Please, please, please don't beat yourself up about this.
I can be a very anxious person myself and I know it must be very distressing to see these traits in your boy because anxiety is a terrible thing. But I agree with the others that I really don't think it's your parenting.
After having DD, I really think they, to a large extent, come out with whatever personality they're meant to have. I barely got out of the house for the first 18 months after DD was born and she really wasn't around many people/other babies and yet, she's very outgoing. My sister and I are like chalk and cheese yet we were parented by the same parents in exactly the same way.
And please don't feel guilty about the separation following the birth. I barely held my daughter for the first two hours after she was born and I really don't see any signs that it has affected her in any way.
I think you've done all you can for the moment and it's time, as the others have said, to seek some more professional help.
As you probably know yourself, when it comes to seeking help it's not really a science. You'll get good advice and bad advice so go with your gut as to what suits your boy the most.
I wish you all the very best and am in total awe of how patiently and gracefully you've handled the situation so far. It seems to me that you've turned out to be a pretty good person and even if your son does have anxiety issues, if he's also inherited your goodness then the world and the people in it will be a better place for having him around.
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