gestational diabetes? Or hypoglycemic!?

Today I had an early breakfast and several snacks at church but at 12:30 my sugar crashed and I almost immediately went from feeling semi-hungry to faint/light headed, overwhelmed to tears, and hardly being able to eat my last granola bar. We drove to Wendy's and I scarfed a burger. 
I've been snacking often during my pregnancy but this weekend I haven't had much protein. Could I have gestational diabetes or just a one off episode of hypoglycemia due to poor diet choices over the weekend? I am 13 weeks today and don't go back to the midwife until Oct. 11.