27 weeks pregnant, if they found acetone in urine analysis, does this mean i have gestational diabetes?

One possibility but: it may not be in your case ,you may not be eating properly remember you need to consume more as you have extra mouth to feed now , You may be eating less , or eating more fat and and proteins not enough carbohydrates , you need to maintain glucose levels need carbohydrates . Drink plenty of fluids eat balanced diet and make sure to see your doctor to find the cause .