Hi Sam,
Welcome to TGH! Nice to meet you. Everyone is very supportive and friendly.
I read your entire post and I feel really sorry for you that your mother doesn’t accept or even acknowledge you. Even if she doesn’t understand she should at least try to be there for you. Don’t worry about comparing your personal journey/experience to someone else, everyone experiences things differently and just because you supposedly have it easier than others doesn’t mean your feelings aren’t valid or painful. I’m also FTM though my chest does not cause me as much anxiety and discomfort as yours does to you, I still feel awful when I see it and I don’t think weight is the problem (I was about 85 lbs when I was 18 and I still hated my chest and changed in stalls). It doesn’t help with the size of your chest though.
No you aren’t just totally insane!
I hope things get better for you and that your appointment with your GP goes well this time 🙂
Good luck, we are all rooting for you! 😀