Could this be gestational diabetes?

Kimberley
I'm currently 24 weeks pregnant. The last couple of weeks I've noticed some days I get heart racing, headaches and extra tired. The last two days I realized its when I eat. I just ate a sub and within 30 minutes my head hurts, heart pounding and now I'm ready to sleep. My doctor told me to wait for three more weeks to get the glucose test. Do you think these might be signs or just regular pregnancy issues?