First of all congrats on your pregnancy. I was 5 1/2 weeks and i had bleeding, more than just spotting and they did both the internal which is uncomfortable but gives them a better picture and a normal belly one too. They didnt detect a heart beat because it was so early and i too cried all day up until my scan but turns out the bleed was outside the sac and most likely from it attaching to my uterus. I went back a week and a half later and seen my lil babies heart beat. I'm sure everytihing will be fine and just think positive.
Good luck and be sure to let us know how it goes.