From the bottom of my heart I feel for you.
I really hope you come to the conclusion to
choose a better life for yourself. You have a chance to take a different path. Take that chance while the window is open. You deserve so much more. I have a friend who went through something similar and chose to break off the engagement and go on a vacation alone to take care of herself. Trust your logic and your gut.
Stay strong and know there are people out there pulling for you.