Gastrointestinal bleeding can give you some clear warning signs or more subtle hints, depending on where exactly in your digestive tract the bleeding is happening and how quickly it's occurring. If the bleeding is more noticeable, you might experience things like throwing up blood, having stool that's black and sticky, or seeing blood along with your bowel movements. On the other hand, there are times when the symptoms aren’t as obvious. You might feel light-headed, find it hard to catch your breath, pass out unexpectedly, feel pain in your chest, or have abdominal discomfort that's a bit puzzling. Given the potential variation among the warning signs it's important to be alert to any shifts in your body that might point to the possibility of gastrointestinal bleeding.