I have only read the first page, so not see all the replies.
My mum left me when I was 4. Not with my dad, but at my nans. I stayed at my dads at weekends. This was 24 years ago and she still won't have anything to do with me.
IMHO, a child never gets over their mother not wanting them. It is a very sore subject for me, even more now that I am a mum myself. I simply cannot get my head around it. I have found out certain details and I remember more than I want to about my time with her. She basically didn't want me and made it plain to SS who continued to do nothing until my 'mother' just left one day when I was at my nans house. We went back to find she had gone and SS knew all about it. Although the original plan was for me to go and be put into foster care so my 'mother' could vist if she wanted to. I don't really care for SS tbh.
It is not something I will ever be able to face properly as she will not talk to me so I can't ask her. Although I'm sure I would end up beating the crap out of her for the total rejection that I always feel. She has made me feel like a totally worthless person. And even though I am happy (mostly) with my life atm, there is always this sense of being such a horrible person that her own 'mother' didn't like or want. That will never go away and I will never forgive her for that. I have very low self esteem and cling to people as a result and take and sort of rejection very badly. This is what any person who was rejected by their mother would feel. I imagine.
So whatever you are feeling, please please don't do it. And also remember that children remember things from a very young age. If you do feel this way, get all the support you can and speak to your doctor (if you haven't already).