Toddler and newborn

Hi mummies, i have just delivered my nb last month. I have a 2 yr old toddler. My toddler was very closed to me and obident. But ever since i delivered, he will throw his temper when he didn't get his way. He will say everything, 'i don't want...' I don't know how to manage him plus i have an infant. My toddler goes to a full day cc.