Hot flashes and nausea are most commonly caused by hormonal imbalances in the body, most notably, by sex hormones. For women, a decrease in estrogen is often to blame, whereas in men, testosterone deficiency can create the problem. Sometimes, the symptoms occur for reasons not related to those hormones at all.
Flu symptoms can be similar to those of a cold, although they tend to be more severe. Symptoms can include: 1  dry, hacking cough. 2  moderate-to-high fever (although not everyone with the flu will run a fever). 3  sore throat. 4  shaking chills. 5  severe muscle or body aches. 6  headache. 7  stuffy and runny nose.
For both the cold in the flu, early symptoms may be similar. Symptoms and signs include a cough, runny nose, and feeling tired. If you know you have had contact with someone with a cold or the flu in the past few days, you should suspect you may have become infected. However, flu symptoms generally are more intense than cold symptoms.