Breakthrough bleeding

I had my first appointment Wednesday (7w5d) which she did a pelvic exam and cultures. She told me to expect some spotting. So I went home and finished off the day. Thursday (7w6d) I had a little light pink/brown spotting which was on and off through the day and I had a little red spotting towards the night. Friday (8w) came and the spotting was still there and still red with some pink/brown every now and then. It was still happening Saturday (8w1d) so I called my doctors office and spoke with the doctor who was on call, which happens to be the doctor who is doing my ultrasound tomorrow (Monday). He called back and said if I'm not filling a pad an hour or cramping bad, it'll be okay but if it worsens to get to the ER. Well today (8w2d) it's still happening but it's becoming less. I've figured out that if I wouldn't be pregnant, my period would've started on or around the 13th. I have a little back pain and my lower abdomen feels bloated so it may just be my body trying to cleanse itself like it normally does each month. Just thought to put this out there incase any other FTM are having or if you come across this issue.