Had a colonoscopy two days ago and ever since then i have been feeling really weak and tired?is this normal?also legs have been feeling restless?

That is unusual: Typically colonoscopy does not cause any such problems. It is possible you had too much of a bowel prep activity(?Severe diarrhea) which can cause dehyderation or electrolyte imbalance. Please hyderate your self with lots of lquids and a pinch of extra salt in your food or drink lots of soups or electrolyte solutions for a couple of days, then you should be fine. Do inform your doctor who did colo.