Just wanted to add that parents are not always like this.
When reading your post I remembered a special father I knew many years ago, he was widowed when his children were very young. With the help of his sister he brought them up in a loving caring home while working fulltime.
When I came to his daughter's birthday party it was full of children older than me - I was a shy little girl, he quietly took me over to this little table he had made for me - it was so sweet of him and even as a 4 year old child I knew he was a very kind thoughtful man. That small action that day has stayed with me the last 40 years.
He has been dead many years now, before he died he sold the family home and moved into a small flat so the money would go straight to his girls (teenagers by this point). Every single action that man made was for his family without expectation of return.
I think of him often, particularly when I hear stories about children who were not so lucky with their parents. I am sorry you have not been lucky with the parents you were born to. It was not your fault you were unlucky. I understand why you fear parenthood and maybe even connection with others too because of this experience. Love is giving without expectations it does not guilt trip.