Pregnancy week 29 and glucose level.

Presently i am 29 weeks pregnant and recently done blood glucose and fasting test in which my sugar level is coming fasting-120 and 75gm glucose tolerance coming 200 However same test i have done in week 8 of pregnancy comes fasting - 97 and 75 gm glucose tolerance coming - 77 Now, presently my doctor recommend me to test sugar 4 times daily at home with glucometer. After which my sugar level fasting coming min - 97 and max 110 some days After 2 hour meal - min 112 and max 143 sometimes. So doctor adviced me to take glyciphage sr 1gm daily at night with proper diet and 15 min walk after every meal. But my sugar level still coming 97 and 149 and tummy is numb also after taking glyciphage medicine. Please suggest is this medicine safe in pregnancy because my weight is not increasing in 7 months