Hi Chelsea95 and welcome to the forums.
It must be incredibly difficult to have to try deal with cruel comments from others when you already feel upset about not knowing your full history for yourself. If I may ask what approaches have you tried when this happens?
Recently I joined an ancestry website to try find information about my biological family (Mum is adopted and doesn't want to even think about it). I'm searching for medical history but you are right there are always questions about who we are. It is ok to want to know because whoever your Father is you've inherited his genetic material. It IS important information.
I paid to have a DNA test. It took about a month and it showed me any members on the website who were related to me and how closely. There were relatives from Dad's tree... But then others I have no idea how I'm related to. One is very closely related (haven't worked out yet how) and she replied to my email.
I knew I needed the confimation from her about my autoimmune condition being present in her family (and it is). But I was surprised at how much the ethnicity results affected me. I've always been asked by strangers where do I come from because I don't "seem Australian". I found out (along with the expected UK, Scotland and Ireland results from Dad's side) there was also Sweden and Germany which were unexpected.
I felt good. Never realised how much it irritated me not knowing when people hinted I didn't quite fit in. But it did.
I don't exactly know what my point is. Perhaps it is simply to validate your need to know. I understand it and relate to it.
Is your Mum able to answer any of your questions? I do understand how hard it is to ask especially if they want to ignore and bury the issue.
Hope you continue to write and find some support here.