subchronic bleeding

So yesterday I was cramping all day, which continued into today so I called off of work. Then around noon I noticed blood when I wiped, let me tell you instant terror! So I call the drs and cant get through so I decided to just go to the hospital. They give me a doppler and get the babys heartbeat, then take my blood. They come back in and tell me that they want to check my cervix which looked good it was closed and no more blood was found. Then they come back in and tell me they want and ultrasound because my HCG levels were high and she she also wants to make sure the baby is growing properly. I was confused cuz of the HCG thats not a bad thing but I wasn't sure at this point. So I go to ultrasound and they start taking dimensions of the baby. As they are trying to get the arm length the baby starts flipping around, they sticks it hand out right into view. So she tries to get the length again and the baby flipped over again. So at this point all I could do was laugh cuz my fears were calmed just by seeing the baby being so active. The tech was even busting up. So finally I was done there. The dr comes back and reports that my HCG levels were high cuz I am a week and a half further along then I was told. But I knew I was further then the dr told me. They told me the blood is called subchronic bleeding? And it is just from growth and pulling in my uterus. So thankgod for that! Funny thing she did say was my babys arms are measuring 18 weeks and 2 days and everything else is 16 weeks and 4 days. I told her that was funny cuz my boyfriend arm spand is unusually longer then normal he is 6'3 and his arm spand is 6'10. She laughed and said no doubt the baby has inherited his arms! No more bleeding for me just some mild cramps but I feel much better. So after a scarey day, I am releived its all over and the baby is an active wiggle worm!