I Feel A Slight, Underlying Sensation Of Nausea - More

I feel a slight, underlying sensation of nausea - more like car-sickness rather than a prelude to vomiting, at times, I have a little cold-sweat & feel slightly shakey (although when I hold up my hands, they are not actually shaking (it's kind of like morning sickness). I've felt it for last 2 days. About 3 months ago, I experienced the exact same thing, which lasted for about a week or so - in various degrees.