I am having nausea for two years now triggered by stressful situations, i was a smoker then quite, but nausea is getting worse, any explanations?

See your doctor: Stressful situation can certainly lead to anxiety and nausea, in those predisposed. But without examining you, i cannot offer specific explanations for your nausea. See your own doctor for a review of your case -- checking your general health. You might also be able to learn to modify your own stress responses, as well. Congratulations on quitting smoking -- that's a big achievement!