Thank you Reggi, for the information,
Blood sugar level depends on when you took the last meal.
Your levels are within normal range.
Besides low sugar, the lightheaded & nausea feeling can be due to different factors.
There may be dehydration, loss of fluid, fall or changes of blood pressure etc .
An infection, anemia can also be factors.
With headache, chill & rigor feeling there is a possibility of infection.
Urinary tract infection can cause chill & rigor. Heart or neurological conditions can also cause those.
As the symptoms are continuing for about a month, you need to get an examination by doctor sooner.
You need to have a few tests like CBC, urine analysis, metabolic panel etc.
Pl take plenty of fluid to keep good hydration, & have adequate rest.
I hope this information helps.
I will be happy to assist, if you need any clarification.
Please feel free for any follow up query.