What Causes Twitching In Limbs And Seizures?

I have been having twiches with my limbs and blacking out alot latley is there a problem here?
Okay so the twiches ive had all my life, i think every one gets them, but now they have been happening alot more, and i just started getting light headed alot lately, and awhile ago i got so light headed that i hit my face off my dresser and had a bloody nose....anyway i was talking to my friends and he said thaat i could be having mini seziures(i dont kno how to spell sorry) and that it could be serious could any one explain to me whats happeing and why? thanks <33