Bleeding after vaginal ultrasound?

I'm 5 weeks pregnant and yesterday afternoon I got a vaginal ultrasound. (It hurt when it was being done) Anyways last night when I went to the bathroom I noticed I was bleeding bright red so I called my doctor and she said as long as I wasn't cramping that it's not an uncommon thing to happen after that sort of ultrasound. So it kinda put my mind at ease but when I woke up I noticed I was still bleeding (stained my panties) So my question is has anyone ever experienced this? And if so how long did you bleed? Mines not like a period but it bright red and over night was enough to stain my panties. I'm not cramping or anything. Just scared.