Struggling with late diagnosis

Hello to anyone who reads this. I don't really know what I'm doing. I'm 34 and got my diagnosis a few months ago and at first I thought I was ok. My partner had a late ADHD diagnosis a couple of years ago and whilst researching things neurodivergent I realized I was probably autistic. I have family who are too but they are on the other end of the spectrum to me and growing up in the 90s/00s it wasn't really a thing unless you were at that end. I don't know what possessed me to get tested, I'd said to my partner I was happy with the knowledge I potentially was but I paid privately to get it done quicker and there it was, the knowledge that I actually am autistic. I've been through the disbelief and didn't tell anyone for a while whilst I processed it but now everyone knows and it's easier and harder. Firstly my family are supportive in their own way, I have always been the black sheep but now I guess it's worse because everyone compares me to my relative. We kinda always were similar in ways but also completely opposite but when she has a meltdown it's acceptable, I still have to mask in front of family. My partner has had his own struggles and that's made us clash on and off which sucks but we're working on it slowly, communication is still lacking sometimes but I know we will be good. Work has been supportive in their own way too, I'm a nurse so have to deal with a lot of socializing, meetings, etc which is exhausting but I genuinely love my job. But I'm struggling to mask, I'm struggling to be the person everyone has seen for so long and I'm struggling mentally. I've never felt so lost or confused or lonely and I don't know how to help myself. I'm on antidepressants, I've reached out to services through work for therapy so hopefully that will help but I can't really put my finger on why I'm feeling like this. Everything is overstimulating, it's too bright, too loud, I can't even have the cat sit on my because it's feeling too much. Has anyone else felt like this? I appreciate any advice.