When reasons are much, but little clarity.

 As within 2 years feeling nausea as constant, maybe you would help me in fight her.

A mechanism for nausea tied with anti-peristaltic or wrong shortening stomach walls and displaying with weakness, sweating, salivation high, coldness in extremities, lowering pressure answers DR. Vorontsov.

A nausea and after vomiting displaying are having in cardiovascular disease, cerebral brain, kidneys, sugar diabetes, parasites, but a most often stomach diseases or neighbour organs  as gall bladder, small bowel, pancreas, liver, bowel.

As you can see a simple list for reason is not allowing to give right advice which would you avoid this bad feeling. And you need to visit for doctor, he will give you prescribe for tests urine, stool, ultrasound, gastroscopy, x-ray for lungs. And its allow to assume  for nausea reason and prescribe for specialist visit and cure a base disease. And in nausea feeling drink cup of green tea or add in tea pinch of leafs Melissa, and sugar changes on honey, and boiling water helping with a spoon of honey, and sour with lemon juice.