INR very low to very high

[shell64]

hi i have just come back from my INR check my range is between 2-3 but its always been low at 1.5 so im on 19 mg of warfarin a day .but for the last 2 weeks its suddenly gone really high last week it was 6.9 and today its gone to 11.1 they gave me some vitamim k on the tongue and i have to go back tommorow for another inr check but im having trouble sleeping .had about 4 hrs last night im either sweating or very cold .just wondering if its the inr or something else

thanks shell xxx