What Causes Twitches In Limbs?

hey, past few months ive been noticing small twitchs throughout my limbs like seeing little pulsing under the skin, also had bigger twitches in my legs and arms where they d jerk suddenly, been noticing alot of weakness too and despite the fact i work out alot at college my muscles seem to be decreasing rather than increasing, also having trouble with my hands like doing up buttons, writing with a pen and more often or not i drop stuff and cant quite hold it properly, is this something that will eventually go away?