Being that you are 42, a possible root of your problem could be ralted to menopause. Following is a link to identify your particular type.
http://www.yourmenopausetype.com/questionaire/mtq.html
It is always a good idea to discuss symptoms such as hot flashes and nausea with your private physician. Nausea related to menopause is not widely recognized, but such cases do exist. Headaches related to menopause appear to be more common. Unfortunately, the connection between menopause and headaches is not widely recognized and they are treated as two unrelated conditions.
Women experiencing increased pain, such as headaches, or increased agitation of any body system, such as nausea may have a progesterone deficient menopause type. Menopause related nausea and headaches are often related to a progesterone deficiency.
It may be because progesterone opposes the action of prostaglandins, substances that increase pain and inflammation symptoms such as headaches and nausea. Of interest; estrogens increase prostaglandins, so may increase pain and inflammation – balance is the goal. Some types of PMS respond well to progesterone for this reason.
As well as opposing prostaglandins, progesterone is more calming or quiescent to the nervous system. Progesterone and its metabolites can calm a body system that is showing signs of agitation - there are increased irritable bowel symptoms with progesterone deficiency. This calming effect is in sharp contrast to the stimulating and agitating effects of estrogens. I have seen progesterone stop menopause related nausea a number of times.
The progesterone metabolites that are more calming to the body include allopregnanolone. This metabolite is relaxing, reduces anxiety and may have analgesic (pain relieving) properties. When progesterone is taken by mouth more of it will become metabolized to allopregnanolone. This may be why I have had better results with oral progesterone than with progesterone cream when treating nausea related menopause.
In any event, please contact your primary care physician to arrange a full work up of possible causes.
Good Luck,
LiddyBea