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.
Flu and the common cold are different illnesses, although they may share some symptoms. You tend to feel much worse with flu, often being confined to bed for several days, whereas a cold will usually just make you feel under the weather. Flu and the cold are both caused by viruses, but completely different ones. There are hundreds of viruses that can cause colds, but only three strains that cause flu. People with flu normally feel very unwell for two or three days, and will continue to experience symptoms for around another five days.