During the light headedness get your BP checked .if systolic is below 80 then you need to tone up with plenty of citrus juices. try fruit juices instead of coffee and catch up with more sleep to beat the stress. relaxation may help. fall of BP can lead to impaired blood circulation and you must lie down during the spells

Welcome to HCM!

After going through your question I have few important points- you have lightheaded, and feel like throwing up any time, many times after having hot coffee, improves with rest. You have low BP from past years.

There can be few important causes for your condition, all well treatable, so please donot worry.

First- it can be due to low BP and may be anemia , so, get your blood counts and hemoglobin checked will tell this. getting thyroid checked will be better.

Second, - if you have some kind of associated neck /shoulder discomfort, please get an X Ray neck done, to rule out cervical spondylosis. It is one of the commonest cause for such presentation.

Third - that you have developed gastritis like symptoms which make you feel light headed and later throwing up...( as you say that it happens sometimes after you have hot coffee- which increase gastritis) . In such cases tablets like Omeprazole twice a day with domperidone helps a lot! Of course it will be good to avoid hot coffee / coffee / hot spicy foods, altogether for some time.

Fourth- that you just have low BP causing this, there is no specific treatment for low BP but maintaining adequate hydration, salt intake, eating some thing every one to one half hour, does help a lot. one should avoid remaining hungry, skipping meals.

So, just get your blood tests and X. Ray as above and you will get the cause for this problem.
Hope the answer helps you
Feel free to ask more questions
Dr. Manisha Gopal