Low Immune System after Colposcopy

Ive noticed since the drama of my Colposcopy ive had a low immune system, ive had a cold evey 4-6 weeks.

Anyone else had the same?  is it a side effect or coincidnce?

This could be why I cant recover, and keep having issues & cant clear this out of my body.

I dont know what to do, I take vitamins, eat a fairly balanced diet (I do still love sugar & chocolate though & saturday night is take away night!).  I hardly ever drink & if I do its one or 2.  I dont smoke.  I walk just about daily at least once, attend one fitness class a week, on holiday I dive daily so im active there as well, I take vitamin C to try and boost myself up.