Two week old won't stop screaming

She wouldn't sleep at all last night or today. She's begging for food every two hours (which is weird for her, she was usually every 3-4) I feed her and then she starts screaming afterwards. I change her diaper, make sure she's warm, I try rocking her, holding her, putting her on her stomach, she refuses the pacifier. Nothing is working. I'm so tired, someone help. Why won't she stop screaming.