Bullet Lag!

I have a Huge Bullet Lag, for exemple if i shot a bullet at someone it take the bullet 1-1.5-2 seconds to actually hit him in spite of the hit marker i have on my screen, but the bullet doesnt have any impact on him actually!
Hey someone help me plz, and i really hope that there are some pro here who can actually help cause i looked all over the web , tried everything but no luck! so i am adressing to you pros to help if not i dont know what to do!