Weight gain anastrozole

Ever since I started anastrozole, I've had the biggest weight gain of my life. I am now officially obese (despite having a double mastectomy of double dd breasts and going flat) and I've had to upsize my clothes twice in the last 4 months. I am worried about the effect obesity has on a recurrence. Has anyone else experienced this? What did you do? My oncologist says it is ok to take GLP-1s but I am hesitant to do it because I have read that you gain the weight back if you stop and I really don't feel like taking another drug for the rest of my life. I eat a really healthy diet generally, don't drink, sleep well and am not terrible at exercising. It's so frustrating.