What Causes Dizziness,fatigue And Urge To Vomit If I Travel?

Hi,

I changed my job recently and I have to travel around 45min in the morning to reach office and 90min in the evening to reach back to home. The problem is, once I travel in the morning and reach office, I always feel dizzy, fatigue and urge to vomit. I cant have my break fast and lunch as well. As soon as I start eating I will sweat a lot and I feel like vomiting. I consulted few doctors about this, and they did brain MRI, Heart Echo-cardiogram, ECG, Abdominal ultrasound scan, Blood test for Hb%, Fasting blood sugar test, T3, T4 TSH level test and so on. But still the have't found anything. All the tests show normal. My BP varies from 80/110 to 90/120. Some doctors its a "Motion sickness". I'm suffering from this from past 2 months or so. Now a day I cant even travel for 15 to 20 min journey in bus. What would be my actual cause. Is there any solution for this, if so to whom I should consult ?