im 42 years female  , im case of hypothyroid and Vit B12 defieciecy on treatment , i suffer chronic constipation which i live with it ,but recently im suffuring tiredness fatigue and bloating after  lunch 

 

my doctor did gastroscopy and biopsy showed chemical gastropathy

 

does any one can explain wht is my condition and the suitable management 

to avoid extreme tiredness after food

thanx