Drop in Blood sugar- Question?

During the night I felt funny, checked blood sugar- 60 mg... Ok 15 gram of sugar.... Waited 15 mintures..... Blood sugar 40 mg..... panic...... eat half bag of skittles...??? nothing called ems.... then 30 min. later it came up to normal...... but fasting was 300 mg??? at first why did it keep dropping ???????????????????????????