I was on Gliclizide for the whole time of my first 11st of weight loss, I still ate low carb whilst on it, what are your BG numbers like? Are you eating differently now you are on it? With my GP support I did reduce my Gliclizide over time & reduced carbs along side that.
My experience was as a lost weight & reduced carbs I had to treat the hypos with carbs which did affect my weight, I eventually came off it & went keto. For me it wasn’t the Glic that gave me weight gain but treating the hypos with carbs. You may need to find your “sweet spot” and get your balance for how many carbs you can eat without gaining weight.
What was your HbA1c? Did the GP explain why they were prescribing you the Gliclizide?