My cockatiel chick approx 40-50days keeps on begging/screeching when she sees me

She keeps on screeching when she sees me, Otherwise she is normal and quiet, Even if i feed she keeps on Making that noise whenever she sees me, I asked a Vet not specifically Avian Vet, prescribed- Melonex, toxomox, vimeral for 3 days, But i am not sure i can give those, Kindly help