Hello and thank you for the question. Answers given are for informational purposes only and are not meant to replace an exam by an in-person. I am Dr. Sohaib, a practicing Internal Medicine Specialist and i will do my best to help you today.
You need to answer a few questions first which will help me assist you in a better way.
Do you get sinus infections frequently?
Are these dizzy spells associated with vomiting? Palpitations? Chest pain? Shortness of breath? Visual blurring? Speech problems or weakness in any body part?
Thank you very much for the useful information. One last question; have you ever had a CT scan for the sinus and ears?
Okay. Well there are many reasons for these kind of dizzy spells you have. Mainly these are due to irritiation or inflammation of inner ear (which is linked to brain to control body's balance and equillibrium). In a sinus infection, cold, or even in any kind of viral infection that can give even a mildest inflammation to the inner ear apparatus, one can have these dizzy spells which may persist for some days to weeks at time; but good thing about these is that these are self limiting and settle down eventually.
There are some other causes for similar symptoms as well such as; circulation abnormalities to brain; cerebellum, inflammatory or demelinating lesions in brain like MS; but in your case, given the fact that there are no other neurological symptoms at all, it is not from a serious cause (like brain) rather the most likely possibility is that the origin is from ears.
Like before, this is going to settle down soon while you continue to take your medicines. You can also use Antivert for symptomatic relief. Have rest. Drink lot of fluids (water/juices). And stay relaxed.
If still you are too much concerned about it, a CT scan of the brain/sinus/ears will give you the exact answer and will rule out any serious possibility (originating from brain) thus putting your mind at ease. But honestly, i dont think it is required.