Room cleaning issues

I don't know if anyone out there can relate to this. But when it comes to cleaning my bedroom it's not something I can see being done by me ever. Not because I don't want to or anything. Because of love yo fix my room and make it ME.  (It was originally my brothers then my older sister's room). But because of actual issues keeping it from getting done .

1. For the first 15 years of my life I shared this bedroom with my older sister. And half of the books, trash,  old toys, stuffed animals, and other random items in here are hers. While quite a few of them are in bags or boxes she had put them under the window for further evaluation and then just left them there. To never go through again. These bags and boxes are too heavy for me to lift and I shouldn't have to get rid of her things. But of course now that she's move out she doesn't see a reason to come back and go through them. (I'm not dissing her I love my sister just when she was younger she was annoying and did make some questionable decisions and tends to forget she left things here or doubt that they are hers.)

2. I have Generalized Anxiety Disorder and Panic Disorder and trying to clean the mess that is my room literally causes me to have a panic attack. I freeze, get totally overwhelmed and want to cry. Added to that i have depression which can make the anxiety even more worse and they all play into each other which plays into why the room is such a mess. But the room is a complete mess and I'm not sure there's enough room for my mother (the only person besides my sister I'd trust to help me clean it) sit down while we work . And she can't stand or twist or bend much. Not that I can either.

Which brings me to....

3. I have a herniated disk in my back , chronic joint pain, and chronic migraines and doing much for a very long time is completely exhausting. Especially when trying to do it all alone. Even if I could do it one thing a day maybe a couple days a week I'm still worried I wouldn't have the energy (or spoons) to do the other chores expected of me by my parents. (I am 22 and pay rent but they still expect chores to be done because they work all day). And the weekend is my only chance to get out. I don't want to give it all up.

Finally...

4. There is so much in my room. And a lot of it is stuff from when my grandparents died, my siblings moved out, or if my parents just didn't know where else to put it. It came to my room. Which isn't fair and is really stress inducing. So I don't even know where to begin. I get a vague idea in my head and then it all snowballs. And I always hear people say how messy their room is but.... I don't know they never seem messy in comparison to mine.

I've considered getting a cleaning service... but asking them to help especially when I know there's trash and stuff on the floor makes me feel bad. Like.... it's my trash I should take care of it not them. I know it's their job and they've seen worse then some papers and bottles but still. And then there's the issue of the clothes and bed and everything. I just... don't know what to do. 

TL;DR: Due to health reasons, and the fact that like 50% of the things in the room are not mine I don't know how to clean my room. Or if I should hire help.