Congrats on the weight loss! You're right it could be a food allergy, or as Dr. A says most overweight people suffer from a carbohydrate allergy. I would definitely dump the BF. He sounds like he is going to be more trouble for you than he's worth. You are on your road to recovery and you do NOT need someone holding you back or encouraging you to fail!
Personally and this is just mo, I wouldn't exercise beyond walking until you are within 15-20 lbs of goal. Exercise can sometimes cause weight gain not only from increased muscle, but if you are not consuming enough protein/fat and calories for the workout, your body will kick you out of ketosis and increase fat stores for latter use.
KUTGW!