Surgery can cause you to misscarry reason why they test before surgery as they will not operate on you if pregnant.
When you have surgery you can have delays in your period due to the shock your body going through. Some people bleed and have a random period due to surgery sometimes very women different.
As I do agree with Chan, I can see a faint line on that test....I would wait another day or 2 and try another test. Of it shows even a faint positive again I would go back to the doctors just to double check.
Thank u and I did I went and seen her yesterday and she took blood work to make sure I get the results today but I was bleeding a little yesterday too and it was more Brown but she told me if I am having a miscarriage there's nothing that can be done but I really don't think I am but it did scare me at first