hi dear, i understand your concern. you have severe allergy, prevention is better than cure. relax, use a mask when you go out, try to be in fresh air, avoid pollution. high blood sugar, you need follow a diabetic chart through out pregnancy, continue insulin, keep a candy with you always if you go for hypoglycemia, monitor blood glucose level. sometime in pregnancy palpitations are common, if you are tired,breathing difficulty,difficulty in going up in staircase,consult cardiologist. i hope i have cleared you doubt.