My dog Has been acting weird she been standing in one place for a long time.. i thinks she sick?

My dog Has been acting weird she been standing in one place for a long time with her head down and nose to the floor,she vomited twice two days ago,and shes Not eating, and when i push on her stomach it hurts her.. theres like big melon size lump in there.. she only jus turn 1yrs old.. any ideas?