When I drink iced coffee (from dunkin donuts, normal cream and sugar) my stomach will hurt (nausea), I'll get lightheaded and all around weak. I will feel a little better if I eat food but it doesn't help too much. The weakness starts right away 5-20 minutes. Thanks so much.

Any number of reasons, most of which indicate a need to consult your own medical practitioner.

Do you get the same reaction from hot coffee on an empty stomach? I agree that a medical examination should be where you seek definitive answers on this.