Need help understanding and coping with situation with Fiancee's Mother

This situation is a little complicated, I just don't really understand what is going on or how to deal with it.

My bf and I have been together for 4 years, and are recently engaged. He is on probation (for about another year) for a crime he committed in the past. His mother has lived in another state from us for the duration of our relationship, but she and I have been pretty close, talking to her on the phone and texting with her at least once a week.

Her husband passed away a year ago, and she has been living by herself since then. She has complained about her arthritis and not being able to do things around the house. Both me and my bf lost our jobs during the pandemic, and money has been very tight.

For the past year she has been talking about us moving down there to move in with her to help us out with housing, and for us to help her around the house and keep her company. We decided to move out of our apartment and take her up on her offer, but agreed I would come back (about 1.5 hour drive) to see my family on weekends (my sister is a single mother and I help out with her kids on weekends). My bf was fine with this, and she seemed ok with it as well.

We moved at the end of August, and things were good at first, but I quickly noticed how controlling she is about everything. It's her house, so of course it's her rules, but it ended up making staying there very uncomfortable. She would get upset if we didn't all 3 eat every meal together, followed by all watching TV together. She didn't like me and my bf spending any time together without her. She and mf bf argue a lot, but it would seem everytime she got mad at him, she would give me the silent treatment. Some days she would not speak to me at all for the entire day, and I had no idea why. I really hate when people are upset with me, but I could never figure out what I did to make her mad so I could fix it.

When I would ask my bf why she wasn't talking to me, he said it is because she knows it bothers me. He said she doesn't do it to him because he doesn't let it effect him so she loses interest. Some days she would be really nice to me and we'd have a great time hanging out together, but then the next day she wouldn't even look at me when I said hello. This has all been really stressful, because we already lost our apartment, so moving out wasn't really an option, but it was clear I was not wanted there.

On Saturday morning of last week I was getting ready to leave for the weekend, had my bag and most of my laundry in my car to take to my sister's, when she said we needed to talk. She explained that because of Covid she wasn't comfortable with me going back and forth between there and my sister's, and that she wanted me to go pack the rest of my things and leave. I was honestly in shock that she waited until I was walking out the door to tell me this. My fiancee was furious because he didn't know she was going to do this either. Because he is on probation and cannot leave the state, I had to leave him behind.

She does have underlying health issues, and even though I take Covid precautions very seriously, I understand her point of view. What I don't understand is why she gave me no notice, or even discussed her concerns at all until I was on my way out. I honestly don't even think this was about Covid, because she goes out to restaurants frequently and never wears a mask, but I guess it doesn't really matter, it's her house. I said "no problem, thanks for letting me know", got in the car and left.

I have been texting with my bf, but reception there is spotty if he doesn't have wifi. She has in the past turned off the wifi whenever she was upset with him. This morning she texted me and told me I needed to come get the rest of my stuff out of her house ASAP, that isn't my free storage space. I told her I would get it by the weekend, but since I don't have a place to stay right now, other than my sister's couch, I'll need to find a place to store it.

Right now she has turned off the wifi again, so I cannot reach my SO, bit when we talked earlier we decided he needs to call his PO in the morning to figure out new living arrangements. I honestly feel worried with him still there.

I am feeling sick over this. I honestly don't know what I did to make her hate me so much. The night before she asked me to leave we all had a nice meal together and I thought things were okay. My SO keeps telling me not to take it personally, but it's really hard not to. He has said she just does all this for attention or to get sympathy from other people, but we were really close for several years, and I'm having a really hard time dealing with this.