Is some cramping normal?

Rebecca
I got my BFP this morning!! I'm 4 weeks 2 days. I've been having some cramping the past 36 hours that sometimes feels 
  little like menstrual cramps. I haven't had any bleeding, not even spotting. Started feeling some mild nausea today too. Has anyone else experienced cramping early in pregnancy? Did your doctor seem concerned? This is all new to me!