Struggles at work with manager

Hi guys, I hope this is the right place to post this. I am really struggling lately. I was diagnosed with a spine tumor a month into starting my new job, I also have ADHD. I started treatment last month and the treatment caused me severe pain. I had to take some time off work as I wasn't able to walk. My manager called me while I was on leave to check up on me, I told him I was doing better but I thought we should have a conversation about reasonable adjustments as I really didn't want to take anymore time off work. I really loved my job, I get to help a lot of people and I am very good at what I do. Its been a very rewarding job for me and has stopped me from going completely mad while I deal with my spine tumor. My manager didn't say much but I assumed we would have this discussion when I returned to work.

When I did return to work my manager told me that he felt I was not fit for the job, that my company wasn't prepared for the level of support I need. I was really shocked by this. I was hoping that I could just have some extra breaks as sitting in a chair for my 10 hour shift made me feel really bad at the end of the day. After, this he proceeded to give me my probation review which he stated that I am abrasive, rude, and negative person to work with. 

I have never been so shocked in my life. I could not believe someone would ever say this about me. I have social anxiety. I am not the most vocal person, but I am a very kind person. I have always valued kindness above everything else. Despite how kind I say I am, I am more so not the kind of person to every have the courage to be rude. I am always so scared what people might say about me. I often worry I get made fun of for the way I talk, things that I like, that I wear wigs, and for generally being an awkward person. I don't have any friends. I moved here before the pandemic and haven't made a single friend yet. I just am struggling to convey that I am not the person he said I am... I feel like this is a nightmare.... I was failed on my probation for being rude.... all my coworkers are great, they have been so friendly and welcoming to me... I would never be rude to them. My manager stated that when I ask questions I come off as negative and abrasive... I just don't get it. I always say please and thank you. I am always so grateful for the help my coworkers give me. 

After my training, my manager asked for my feedback and I told him that I felt the training was a bit disorganized and didn't fit well with my learning style. In the probation review, he stated that I made negative comments about the training... I thought my comments were very constructive. I am always someone that is careful about what I say. I don't understand why he asked for my feedback in the first place. 

The most ridiculous part of this is that my manager isn't exactly the most positive person to work with. Every shift he makes negative comments about other employees and their work. He once spent an entire shift discussing a previous employee extremely rudely, calling him a "git" and making fun of him. While this really upset me, I didn't want to bring it to anyone higher up as I am still new to my team and the only female. I don't want to come off as a snitch and be hated. If anything his negative comments about other people just pushed me to make sure I was behaving my best as I didn't want him to talk about me that way. 

Apologies for the long post. I just don't know what to do. I feel like my manager wants me off his team because I have had to take time off work for my spine tumor. I don't understand what other logical reason there could be unless I am completely delusional. I have a meeting tomorrow with another manager to discuss it. I am so scared. I am already devastated that I have lost a space I felt like I could do my best work. I worked so hard and put so much of myself into this job and I think it shows through my numbers. I don't mean to be dramatic but this is just the worst thing to happen to me. I have never been so sad about something. I don't know how I am going to get through this. I just feel so hurt. 

Have any of you gone through something like this?