I am so very sorry for what you have gone through with the loss of your son. I too lost a child which until I read your post I thought I was over the grief but it's surprising how it doesn't take much to trigger those feelings again.
I was told that it didn't matter too much because I didn't give birth to my child. It was fairly early in the pregnancy so even though they knew the sex of the baby they said it was best I didn't know, like it would be easier to forget about it if I just thought of the baby as an 'it' rather than my daughter or son.
Instead I have wondered every day since whether I lost a girl or a boy, it's like I'm missing a piece of me. I'm now unfortunately unable to have children due to something that was done to me by someone who I thought loved me. It's so hard to move on with that knowledge but you seem to have realised that it doesn't change how strong of a person you are and that just because you don't have a living child doesn't make you less of a person.
I understand how you feel about your parents reactions and your in laws reactions because mine were the same. I was told that I was a failure multiple times because I was not doing what proper women are supposed to do by becoming a mother, like that was my only job in life. My parents even changed their will which excluded me and gave my share to a niece because she had children so she was better deserving of their money than me.
I didn't care about their money but it was the principle of the fact that I'm still their child and I deserved to be considered as such. It's not like my niece is poor, she is very well off. I'm sorry I'm digressing but I've been thinking a lot about things lately and your post brought it all back up again.
I hope that you can find the help you need to fully grieve because I know that I never truly have. I tried at the time but I was told that because I didn't give birth to the baby it didn't get recognised for grief counselling. That was a long time ago now so I will follow your journey and maybe you will be able to share what is helping you only if you feel comfortable to because I know a lot of people are suffering the way you are.
Thank you for sharing your grief and I'm sure helping not only myself but others in saying it's ok to talk about and it's not a taboo subject. I wish you all the best.