For About 5wks I Have Had A Pain In My

For about 5wks I have had a pain in my head not a headache I am having spells when the room spins this happens not only when laying down but sitting and standing when I shut my eyes when standing it feels like I am going round and round, My GP has stopped the blood preshire tbs I was on and lowered the propranolol from 80mg to 40mg this was on Monday its now Thursday and as yet their has been no change about how long will it take for me to see any changes