What Could Be Causing My Sudden Fatigue, Body Aches, Headaches, Nausea, And Hip/thigh Pain Given That I’m Vegan With Anemia?

I have general aches, very sore back and left hip down the side of my thigh. Fatigue, serious headaches over the past 2 weeks (I rarely get headaches), sometimes nausea. I am anemic, a vegan and 55 years old. I am very active and in excellent shape, so this unwell feeling is very out of character.