Insertion of IUD does not appeared to be related to your problems.
It is difficult to come to a conclusion regarding your problem, with the information provided by you.
More details are needed like the dizziness is true rotatory type or not, is it severe, does it come in attacks or present all time, how long it lasts, any hearing impairment
, any noises in ear, any ear discharge
,any nasal symptoms etc.
As you have headache and double vision
also, it is important to examine you to find out what is your problem.
For all of this you consult a good ENT specialist
If you don't have ear discharge, you may need to consult an eye specialist for double vision problem.
Please consult a neurologist
regarding your loss of sensation in feet.
Wish you good health.