Your brain feels that way because it's in a Fight or Flight mode.
You chose to remove yourself, and honestly if was a second time around it was a smart choice. He has clearly showed you who he is.
Know this - You deserve better, you deserve to be treated with kindness, love, and above all respect. He is incapable of that.
You also did NOTHING to cause this, and your gift of R the first time was more than enough to be content with knowing you did what you could.
If you are still strung out, and frantic, and cant stop the brain, and aren't able to eat or sleep, please talk to your dr about something for anxiety.
I remember in the early days I went days and days without real sleep, it made it so much more difficult to keep my emotions in check. I found the antianxiety medications stopped my brain, and allowed me to get real sleep, and that in turn allowed me to be strong, and control the negative thoughts.
Do one nice thing for you today. Even if it's small. Take a nice long bath, get a pedi, read a book (non A related), watch a Will Farrell movie, something to make you feel happy.
You have a new start, and you will come out the other side of this stronger than you could have ever imagined.