I appreciate your concerns as you are 22nd week pregnant. Ideally a women should gain around 10-12 kgs of weight during the gestational period of 9 months. But you have gained almost 10 kgs in 22 weeks. My advice is first you get your laboratory test for blood and urine sugar done. Then get one Abdominal ultrasonography done to see the growth and size of the baby. Then a specific therapy can be initiated. Meanwhile do moderate exercise for 10 minutes in the morning and evening. This will reduce excess fat deposition in your body, avoid fatty and oily foods.