Try to match energy intake with energy expenditure.
Your shake has too many calories and/or is too high GI for your level of exercise. Likely your blood sugar is rising too fast and trigger insulin secretion and you are getting corresponding hypoglycemia. Either gradually consume your shake throughout your exercise or switch to a lower GI meal so that energy intake is spread out over your exercise interval.
Large, high-GI, meals are best left to post workout where you have created a large energy deficit.