@amyboylan1, for others reading here, I'd also like to insert a link to another discussion you started as well as others about diet and MGUS

- Does plant-based eating lower chances of MGUS progressing to myeloma? https://connect.mayoclinic.org/discussion/plant-based-eating-to-lower-the-chance-of-mgus-progressing-to-myeloma/
- MGUS diet: Any tips on food to enjoy or prevent progression?
https://connect.mayoclinic.org/discussion/mgus-bgus-diet/
- What’s the science on diet and MGUS/SMM?
https://connect.mayoclinic.org/discussion/whats-the-science-on-diet-and-mgussmm/
I rephrased the title of this current discussion to better reflect your question. You are concerned about your weight and potentially causing the progression of MGUS. As a non-medical professional, I'd like to sit across from you, offer you a cup of tea and just have a chat. Here's some of the things I'd say.

Good for you for taking care of your mental health along with your physical health. You're taking anti-depressants because you and your doctor likely talked about how they can help take the edge of and help you manage better. It's true that some people gain weight on anti-depressants and it can be a real struggle to lose it. That's okay! Eat well and worry less.

Deep breath!

You've read that being overweight "might" cause progression of MGUS. As @hsminc kindly pointed out, the research is limited. I suggest focusing less on being over a normal BMI and more on eating well. Enjoy good food and forget the scales.

Deep breath!
Focus on living. Eat good foods, stay active socially and physically, and do things you enjoy. What are some activities that you enjoy that keep you active with other people?