<human>: Me (21F), SO (20ish M) and mother (50ish F).

**Background** My mom has been abusive for the majority of my life and she has spent the last 11 or so years making fun of me (Ie. Telling me how fat I am, telling me I am a failure and worthless ect). Tonight, against my better judgement, me and my SO got high with her because he has been pining for weed for the last two weeks. 

**Problem** My mom spent the whole night belittling me in front of him and even flashed him twice. I understand how this might sound funny but all I keep thinking about is how she crossed the line with my SO, I feel like she flashed him because she wanted him to think about fucking her, why the hell else would she do it? I feel like she betrayed me and my father. 
To top it off, I was having anxiety attacks for the later part of the night because of some not to pleasant things going on. I told my SO I wasn't okay and he went out to get high with my mom anyway.

I feel like things are not okay and I don't know how to make it all better or go away. I tried to talk about it to my mom and she told me if I didn't like it I should get the fuck out and when I tried to talk to my SO about it he honestly had no idea what I was talking about. I know its not his fault, he couldn't stop my mom from flashing him but I feel like he could have said no and I feel like he didn't have to laugh at her jokes about me or get high with her while I was really not okay.

What the hell reddit, am I crazy and needing to get over this and forget about it? Or does me being upset about this make sense to anybody else? I really need to know what to do from here, please help and give me some perspective. 

I just want to know if I am crazy and how do I move on/forget about this.

Can you condense the text into a few key points?
<bot>: Abusive mom crosses the line with my SO, my SO continues to get high with her. I feel like this behavior is not okay but I'm starting to feel like I am crazy. Help?