Bleeding of confused

Today actually the first of Jan I woke up because I started bleeding light cramping but when I pee straight flood of blood I call the ambulance and I go str8 to the hospital I get there I'm in tears knowing feeling thinking I lost my baby but when they do a ultrasound they say it's still early can't see the baby in your uterus. Remind you I'm 4w4D so They say well your HCG IS UP 263 to 463 I asked y I'm bleeding They tell me they don't kno They Think ectopic pregnancy So Now sitting here TEARS not understanding y they let me go home and I'm still bleeding no clotting not even severe cramps very mild every time I go to the bathroom str8 blood nothing in a pad not feeling up a pad I'm not understanding I'm confused?