Hi, My father took a early morning bus (4 am - very very cold ) from Chandigarh (he had just received news that his mother has died so he was rushing to his home town). After around an hour,he started to feel dizziness even when he was sitting. In next 1 hr, he vomited (nothing came out). In 30 mins, he vomited again. In next 1 hr, he had to take another bus so he dropped out of bus and immediately felt severe dizziness so much that fellow passenger had to support him. He finally reached destination. His situation got better but he continued to have difficulty if he has to walk on uneven surface. Then he went to sleep for full night. Nxt morning, situation improved but very light dizziness still there. What could be the reason? (His angio was done 18 months ago. One stent inserted when his blockage was found 80% in one of main artery )