Symptoms of Low Blood sugar?

Ok I'm 15 yrs old and I'm on the cross country team at school. Today's practice was a scorcher and something disturbing happened to me. I was almost done with my run when my face started to tingle. Slowly my whole head started to tingle or go numb. I became very cranky and snappy with my team mates. When I started to get frustrated I started to cry and couldn't stop. A while ago this had happened to me and my mom had a blood sugar tester and tested me and said that my blood sugar was low. I think that it was under 80 or 75. Is this typical of low blood sugar.