I can't really see anything wrong with her. She looks very good, and I can't even notice that she was ever thin.
If she is pregnant, you must keep us posted on what all happens, and then when the foal comes you must post LOTS of photo's!
Is your boyfriend just planning to use her for pleasure riding or is he thinking of competing?
Very gorgeous horse by the way! I just love how her face is darker than the rest of her body.