Should I be worried?

Alyson • I have a 1 year old son and currently pregnant again due May 5th 2016 ♡
I woke up this morning with really bad morning sickness and then I started feeling better later on. Well now my lower back is in really bad pain it feels just like when I was in labor with my son. I'm only 8 weeks and 4 Days. I called the doctor and waiting on a reply. Should I be worried or go to the hispital? I've never had any bad symptoms with my son so I'm clueless