A few weeks ago i had a convulsion, ever since then, whenever i get up i feel dizzy, my ears start ringing, my vision goes blurry/black, and sometimes i start like shaking/twitching (as if i was having a seizure), to the point i collapse, i feel this?

You should see your doc or a neurologist ASAP

If you indeed suffered a generalized tonic-clonic epileptic seizure, you would likely require anti-epileptic drugs to prevent further events. Your current episodes sound more like syncope. Until all of this is fully controlled: AVOID DRIVING, activities at heights, use of power equipment, taking baths or swimming alone. See a neurologist ASAP.