I've felt terrific and energetic for a long time. Three days ago I started seeing blood in my urine. Now I'm feeling a bit sleepy and head-achy. I have mild discomfort in lower abdomen area (not exactly pain). Is this a urinary tract infection or might it be a symptom that my blood thinner (warfarin) dose should be lowered. Messaged my doctor but no response. I'm 71 years old and am not prone to UTIs.