your symptoms are classical for what we call SYNCOPE
what we need to know is why is it occuring. most situations they are precipitated by certain stimulus, such as heat, sudden pain ,fear etc. but incase you say these symptoms have come out of nowhere. likely cause could be cardiac then. change in heart rhythms can lead to decreased blood flow to the brain and precipitate the attack of syncope.
read about cardiogenic syncope.
get a 12 lead electrocardiogram or ecg. may need a tilt table test
. every time you are aware that this is going to happen so it is unlikely to be anything neurological such as epilepsy
. it is likely that a ecg may be normal when you are comfortable , but when you have symptoms we can exactly see what change in heart rhythm occurs episodically to point out to the root of the problem.
the frequency of your episodes are not good. so see a cardiologist. to know more about your disease read about CARDIOGENIC SYNCOPE. I really dont think you have anxiety
to blame for occurence of these episodes.
hope this is helpful.