What Causes Dizziness During Periods?

hi i was wondering if you could help me for the past 6yrs i have been feeling dizzy 24/7 the feeling as thought im going to pass out, ive had ct scans mri scans and inner ear tests blood tests but come back clear it gets even worse during a menstral cycle..i get hot flushed and cold hand ive had the test for menaplause and it came back negative..im 34 years old i was wondering if this could be something to do with my hormones i also get high pitched noise in my ear and sometimes loose my sense of smell help me please