Unusual fatigue, derealization for past 0,5 yr. anxiety, panic attacks since 1,5 yrs starting with muscle cramps. can it be magnesium deficiency? 22/m

Unlikely Mg deficien: Severe magnesium deficiencies are rare, can be due to kidney disease, Crohn's disease, problems with parathyroid function, or related to drugs for diabetes, cancer, and some antibiotics. Anxiety and panic attacks are often accompanied by depression, which can produce fatigue and derealization. Get physical checkup from MD, then consult psychologist for evaluation. Good luck!