Feeling weak due to very low vitamin D levels, high blood pressure, and early white hair may be partly related to overall nutrition, stress, and lifestyle, though no single issue causes all of these. Low vitamin D can lead to weakness and tiredness, while blood pressure is related to diet, weight, and activity, and early white hair can be genetic or due to stress or deficiencies. Focus on a balanced diet, regular exercise, good sleep, and daily sunlight exposure to support your health. A doctor may advise supplements and medicines as needed, so consult your doctor for proper guidance and follow-up.