Warfarin intake time

Hi. I have been taking 7mg a day for appx 6 months - this was for a P E in left lung, I`m 50 yrs old ( male ) - my INR is average at 2.5. The P E seemed to be caused by a gain in weight - a gain in blood pressure - a job stood on ladders regular for about 2 months up to the clot ( don`t know whether this was contribution or not ) also a very long car journey pre clotting. From the sound of this case - would it be safe to cut down or stop the warfarin intake anytime soon or will it be longer term. Any idea`s would be most welcome - I am just starting to get a headache or two in the last couple of weeks which I`ve never had before. Any thoughts. Thanks I.