Early Ultrasound

I started spotting today so I went to the ER and they gave me an ultrasound and a vaginal exam. They determined that I have a slight bacterial infection, which they said is common in pregnancies. They also said that my cervix is closed and the blood looked old, possibly implantation bleeding. I was given an ultrasound and they determined that i measured about 5 weeks along, which is less than originally thought, however they did not see a yolk sac or fetal pole. They said to treat the infection and follow up with my obgyn. They said there is no real cause for concern unless i experience severe cramping and bleeding. Has this happened to anyone else? Also, my whole lower abdomen was really sore after leaving the ER. Do intervaginal ultrasounds leave you feeling sore? She was digging around quite a bit.