Autistic and struggling with adhd child

[Whenthesunshinesup]

I wasn’t sure where to post but I’m looking for advice please.
Step daughter is almost 10 and for the past 2 years I have noticed she has every symptom of ADHD. I have a sibling with ADHD and knew the signs fairly quickly. No one believed me and thought I was using it as an insult rather than to get her the help she needed. Finally DH and other relatives noticed how much she had suddenly changed once I guess the masking had become harder for her, she’s now in the process of a diagnosis and getting the support she needs.
I myself have autism, I struggle a lot with socialising and get overwhelmed quickly around other people. I need regular time through the day to close off and be alone in quiet.
However with step daughter having ADHD and quite literally bouncing off the walls 24/7 I find we now clash constantly. Neither of us can help how we are but it makes us both miserable. Step daughter being told to calm down and watch tv when she physically can’t, and having her in my face when I’m trying to get away is all so much for us both and I can’t cope anymore.
This morning has been so difficult I locked myself away crying because I’ve been over stimulated again and had numerous panic attacks. I’m now at the point where I think I either need to stop having a relationship with step daughter and go elsewhere when she stays, or to leave. It’s a situation that can’t be helped and we’re both equally uncomfortable, no one is to blame and trust me as the adult I have tried so hard but it distresses me a lot. She is extremely hard work and never stops to keep still and never sleeps either, even if I come away for a break I can still hear her which still affects me the same.
Obviously she has to come first for DH so naturally he supports her first and foremost, but it’s having a negative impact on me being around her. She’s also complaining that I’m too quiet and I don’t play with her in the same hyper way she can. when she goes home I’m fine and I can finally relax and feel comfortable again.
Can anyone share some experiences or advice please?

Anyone please?

It sounds like you could use some help establishing boundaries so that your competing needs don't clash. I think talk to DH and explain you need down time while SD staying, and maybe agree that if you go to a bedroom, your not to be disturbed, but maybe that you won't stay in there for more than 30 minutes at a time, so it doesn't become a hiding place. More like a battery recharge.