Since April last year, I've been experiencing a lot of lightheadedness, dizziness, feeling tired and drained quite a lot, whenever I get the lightheadedness, I start sweating and feel tired. I am also seeing changes in my menstrual flow, sometimes 3 to 4 days and sometimes normal 5 to 6 days heavy on the second day. I've done MRI, ECG,Echocardiogram,holter, the MRI showed a small anyurism and i was told that its not the cause, Echo showed trivial regurgitation and was told that is not the cause, atrial fibrallation and supraventricular ectopy showed on the holter and again i was told that none of these are the causes. Can this be symptoms of pre-menopause. I am 47 years old.