What Causes Feeling Of Brain Turning Over?

I GET A STRANGE DIZZY SHARP PAIN IN MY HEAD. FEELS AS IF MY BRAIN IS TURNING OVER! HAVE BEEN TAKING WARFARIN FOR > 15 YRS AFTER 5 DVT'S. I AM 57 YRS OF AGE. NOT OVERWEIGHT AND HAVE HAD UC FOR >35 YRS. NOT FEELING TOO HEALTHY AT THE MOMENT WITH CHRONIC FATIGUE AND VENOUS LEG ULCER (3RD TO DATE).