Sometimes I feel sick

hiyomi

So, basically sometimes I feel randomly sick, like nauseous, tummy twisters, and just uglyish. I don't really know what it could be. I'm eating 1500-1800 calories a day, mostly healthier food, for the most part. I exercise Monday-Friday, 1 hour cardio and then weights. I randomly get these little sick spells, sometimes while eating, sometimes while just sitting down. I'm not particulary hungry, at least I think I'm not lol Anyone know what this could be?