Oldest & babies

I have 6 kids& my oldest is 18 . He just graduated out a high school, the last couple years he's been rebellious a smartass and not the kid that I raised . I don't know what bug went up his butt he is the oldest he's been the only boy until now . I have a 3 month old boy and he acts jealous he doesn't want to admit it but his attitude and behavior makes me feel like I don't deserve to be happy having another son all of my daughters are happy and ecstatic that we have more kids in our family but he just makes me feel undeserving of another boy. more or less ever since he found out I was pregnant with this baby he's been a jerk towards me.