A feeling of being off balance.

Hi all, im looking for some advice really, about a month ago i had a cold, the cold cleared up but i was left with a stuffy nose, pain in my cheeks and eyes and bright green discharge from my nose. I spoke with my doctor and she said it seemed as though i had sinusitis. I was given some antibiotics and a nasal spray and the symptoms seemed to get better. Anyway, a few days later i noticed that when i was walking i felt off balance, not dizzy as such, but more like if i moved too quick i might fall over. I also have pain around my cheeks and my ears at times feel full and they crackle too. My eyes feel sore, almost like they are dry and scratchy. Some days the off balance feeling isnt too bad, but some days like today is seems to be quite strong. I also get this feeling in the back of my head like pins and needles or as though something is crawling on my scalp. I feel generally ok in myself, but because i have been reading different symptoms on the internet i now am thinking i have a brain tumour. Im very stressed at the moment as my dad has terminal lung cancer, and i suffer badly from generalised anxiety, so i guess i want to know whether its something serious or whether its still the sinusitis playing up.

Thank you in advance.