Hi,
Your symptoms may be explained as presyncope.
I want to know about
1) Presence of diabetes,
high blood pressure problem, cholesterol problem if any.
2) Current medication if any.
3) Habits like smoking, alcohol.
4) Any recent illness like loose motions, vomiting,
excessive sweating, high grade fever.
I will suggest you to undergo following test
1) ECG electrocardiogram preferably during episode.
2) Holter's monitoring, electrophysiological study of heart.
3) 2DEcho (echocardiography)
4)
Complete blood count, hemoglobin level.
5) Blood pressure check in supine position and In standing position to know
postural hypotension.
6) If all these tests are normal then there may be need of MRI brain with angiography and carotid artery doppler.
In your case there may be possibility of
Cardiac arrhythmia (abnormal electrical activity of heart), postural hypotension, problems related to blood supply of brain.
These symptoms cannot be explained as perimenopausal symptoms.