thank you for your query,
what your experiencing is called as Pre-Syncope
Its a prodromal state that often includes dizziness
and loss of vision ("blackout") (temporary), loss of hearing (temporary), loss of pain and feeling (temporary), nausea
and abdominal discomfort, weakness, sweating, a feeling of heat, palpitations..
in most patients it usually leads to loss of consciousness
there are three main causes for it-
cardiogenic, reflex and orthostatic hypotension
other forms include vaso-vagal syncope,orthostatic syncope
the basic mechanism in any form being decrease in blood supply to the brain for a short period of time.
a full physical exam should be done to pinpoint the cause
the following investigations can be done-
1.complete blood picture
3.tilt table test
these should be able to clinch the exact diagnosis..
you can contact me for any follow up questions