I may not be as far along as I thought?

Jennifer
My lmp was October 8. I didn't have intercourse until the end of the month so between the 20th-27th. I had light spotting 11-11 and a positive pt on the 12th! I had my hcg done yesterday and it's at 3284. I've had slight cramping intermittent and light spotting. Just when I wipe or pass a Bowel movement. I have all the symptoms... sore breasts, frequent urination, increased appetite, dull headaches... can anyone she'd some light? This is my 5th pregnancy. I only have 1 child. My last pregnancy was in 2007. Please help me. Oh and an ultrasound was done on a machine not specifically for pelvic but it works and no sac was visible. That was last week...