I am having a medical problem that has not been solved as of yet?

I am a 76 year old woman who is having a medical problem that has not been solved as of yet.
I am diabetic but that is under control , I am type 2 diabetic. I began to loose my appetite and did’t feel like eating therefore I lost about 15 lbs, what is terrible to me is that my face is sunk in plus I have lost muscle tone, I became very weak and fatigued. I ended up in the hospital over the Christmas holidays.Many test were run and the only conclusion they came to is that I had low magnesium which caused my blood sugar to become low . As of my last test showed that it had not come up after few weeks .Yes I have been under stress because of problem my grandson has ad and he lives with me but is 41 years old and had not lived with me until a couple years ago, His Mother died , he lost hi job and couldnt find more work in our little town he came to live with me I had cancer once unidentified but took radition . blood test did not show any cancer markers> I do have small lumps under my skin , legs and arms but the Dr. did not think much about that.
Could these lumps be of any threat to my health ?I am weary about my weight loss for I look sickly in the face mainly.I weight 127 lbs and am 5 “4 inches tall .Do you have any insight as what my condition may be? thank you