Difficulty in breathing, sudden twitching of limbs, internal shaking at night and easily forgot things, what caused all these? What happened?

Hyperventilation. These are classical symptoms of hyperventilation (overbreathing). When you breathe too fast and too deep, you wash out carbon dioxide from your blood and cause alkalosis. Alkalosis pushes calcium into the cells causing temporary hypocalcemia in the blood. This hypocalcemia causes muscle twitching and even sometimes tetany.