Yes you could be pregnant or have viral stomach flu. See your doctor for a blood test.
yes.
no
Take a test
there is a lot of reasons like you are pregnant or you have a problem so go to your doctor and find out if your not pregnant
i havent heard they can but my gerbil wiffy's head was shaking for a while one time so maybe they can have headaches
No
It's quite possible.
yes, as long as you havent gone through metapause
no.
no, if you havent had sex.
Stress, change of life styles, it could be a many of things.
Maybe its because u havent got enough sleep or becuase you r skipping meals. Eat! Sleep!