Pembrolizumab

Hi I would like to discuss the effects of pembrolizumab.I recently started a course to treat neck and lung cancer.Unfortunately three days after starting my first treatment I picked up the flu which hospitalised me for 5 days.My lungs were badly affected and still are but not as bad.Im wondering is the effects I’m still feeling a result of the flu or is it the effects of the treatment?I had no issues with my lungs previous to starting my treatment.