How Long Does A Balanced Diet Take To Alleviate Fatigue And Exhaustion?

HI, My doctor ran a test of urine and blood( draw first in the AM) I am 75 and been told I have the left ventricle ejection faction ok heart failure. The blood draw showed me so low in almost every vitamin and mineral that it was terrifying. I eat well -no sugar, low carb, lost of protein but hardly any vits and minerals. So two months ago I began a lot of fruit and vegs in my diet and I do think I feel somewhat more energy and less fatigue. My doc tended to be over conscientious in the past so I thought he would jump right to cancer so I did not go back. How long is it going to take for improvfement and is there anything else I can do to add energy. I cant keep up my housework and that is a big issue for me. No offense about not going back to doctors but in my area they predict such awful things that I cant take it anymore . I am very encouraged that I don t have the crushing fatigue and exhaustion that I had before and I am getting better, it is just so slow. I am destresssing the demands on me by eliminating difficult emotional issues . What else can I do. ? I believe I am basically a healthy and strong person but somethink I am doing is not working well. Any ideas very much appreciated. (I am overweight, not obese, tend to high blood sugar unless I am very careful of my diet, cant seem to handle carbs well, hate exercise due to the fatigue) I don t smoke , drink socially. Take vit c powder, nutrional yeasrt and one a day vit . Trying to detox with bentonite clay. Tend to constipation. /Thank you for applying your experience and wisdom to my issues.