What Causes Headaches And Nose Bleeds?

Hi, I am a 40 year old woman who has recently began exercising daily. I have started to get quick sharp headaches several hours after I exercise, and I also get neck and shoulder aches. For the past two days, I have also had nosebleeds. Is it possible that this is related to exercise? I am overweight and have slightly high cholesterol. I also bruise easily and have suffered from fainting spells since I was a child. Years ago, my doctor explained that the fainting spells are related to circulation. If I'm not properly hydrated and I stand for too long, especially in the heat or while taking a hot shower, I can feel a dizzy spell coming on. I also have a history of heart disease and stroke in several members of my immediate family. Obviously, it is imperative that I lose this weight, so I have been increasing the intensity and duration of my workouts in order to achieve that goal. However, because of my family history, I am concerned that the headaches and nosebleeds may be connected to my exercising and may be symptoms of a more serious heart related condition. I apologize if I sound like a hypochondriac, but heart disease has claimed the lives of many of my family members while they were in their 40s and 50s. Should I see a doctor about this, or am I overreacting?