This is Dr. David
you could be fighting off a viral infection.
you could be having some low blood sugar which can cause headaches sometimes and not feeling well.
you should quit smoking
viral gastritis can cause upset stomach and nausea symptoms.
brain tumors causing headaches would tend to cause headaches and vomiting and seizures and stroke like symptoms and the headaches wouldn't get better until your tumor was treated.
withdraw from caffeine can cause headaches as well if you are not drinking your usual coffee
not getting enough sleep and not drinking enough fluids can cause headaches.
let me know if you have other questions.
if done for now, please leave positive rating above the chat box so I can get credit for helping you today
we only get credit for helping clients after positive feedback
you can always reach me with "a question for Dr. David" in the medicine or oncology categories if you have any other questions
here is my website if you need to reach me again:
Thanks for using JustAnswers.com