Thanks for the query to H.C.M. Forum.
Hot & cold flashes, headache,heaviness above eyes, all are just from three days.
But the root cause of disease is pain in knee from the last 3 weeks.
Excruciating pain in itself causes fatigue,nausea, dizziness
Pain in the knee may be due to ,
Injury ( unilateral pain),osteoarthritis
So many causes are there so consult an orthopaedician and get his opinion.
X ray knee may reveal underlying disease.