Why Am I Losing So Much Weight Despite Eating While Having Diabetes And Breast Cancer With Recent Lung Metastasis?

I am a type 2 diabetic and I have lost a lot of weight and I can t seem to get any weight on no matter what I eat I am a 72 year old black female and when I was in my youth I was skinny but not like I am today my kids think that I am too skinny and so do I am trying to keep my sugar levels at a good read and the readings are all over the place I am a breast cancer survisor of ten years but almost a month ago it returned but now in my lungs and we are in the process of treating it by radioactive lazer to begin on nov. 6, 2018 so I am not sure if I m doing to much or what but nothing has anything to do with my weight so I m just trying to hang in here and try to figure out some other alternatives hopefully thru some suggestions from any of you I have not spoken to my primary doc. of my concerns or really anyone these other things are coming so fast at me that when I go to the different doc. my mind just goes a complete blank even if I write my questions down but I m a positive person and I m dealing with my situation the best I can and I just looking for some alternatives that I have not considered yet if you can help I absolutely would appreciate it very much but if not then its all good I will keep trying to work on myself the best I can my weight ranges between 125-128 and I am 5 and a fairly happy reasonably person I have my faith and trust in the almighty and I have come to realize that it is wha it is and I can t fix it so I will deal with one day at a time thank you so much for letting me vent and I will be grateful for any suggestions that anyone has.