Galvus met issue. A new med. pls advice.

Hello..i am asking this question for my MIL who is 56 yr old. She is being treated for type 2 DM since last 6 months. When medication started, she had borderline sugar, so doc gave her just metformin 200 once a day. She was normal, did walking n exercise. A week ago, her fasting sugar was 149 n pp was 210. Her doc gave galvus met 50/500 twice a day. She is not feeling well since she took new med. She feels weak, upset stomach, loss of apetite, major headache, n she cant even go for a walk. Dietician has asked her to eat 1600 kcal a day..she cant go beyond 1100 kcal max..as she is suffering so much. My question is that is this a side effect n will pass or shall i consult her doc again for a new med. Pls advice.