Low blood sugar?

It seems I can't go 30-60 minutes after eating without feeling shaky and weak. Yesterday after 2hrs I was so weak I couldn't move and was so cold despite the summer heat. I passed my gestational diabetes test so I know it's not that. Has anyone had this before? Is it low blood sugar? I'm seeing my midwife Monday so I'll talk to her then but was curious if anyone else has experienced this and what you did to help (I have a hard time eating every 30min).