Hello. Welcome to hcm.
Varied symptoms like this can be infection like pneumonia
or chronic disorders which immune deficiency
I adivce you to undergo fever profile which tests for most of infections,usg abdomen, xray chest,complete blood examination,hiv,tuberculosis
antigen test. Hospital admission will be better to manage hydration and i.v. antibiotics. Once diagnosis made,it can be treated accordingly.
All the best