As you have mentioned you have DVT and you are on warfarin
you have not mentioned about your PT and INR Test. Whether PT and INR is being done to monitor dose of warfarin or not. Your sinus tachycardia
may be due to anemia
.What is cause of anemia .Your other symptoms also may be due to anemia. Get your PT and INR done as if it is raised it may cause bleeding and anemia.Consult your GP and get your anemia corrected.