Under my eye has began to twitch, and it worries me immensely. i also have anxiety and i work and have been having dull headaches. i feel more when i bend, stoop, or walk. what could this be? is it serious?

This is a eyelid myokimia, which is usually a self limited thing, it is aggravated by stress, lack of sleep, too much caffeine or use of oral decongestants.. Suggest changes in stress and lifestyle and if this does not work further evaluation is needed. Botox can be given in recalcitrant cases.

Yes, you have orbital myokymia, which is benign, self-limited and will remit spontaneously. You anxiety and headaches may need attention, so, contact your doctor, discuss your problems and decide on next steps.