Implantation bleeding or? Tests.

So my gf and i are having lots of sex. But unfortunately when her period was due on april 22, she didn't have her usual or scheduled menstruation. But she did have a week early menstruation last march, so we figured that it was nothing to worry about. But on may 1, she had a white discharge that lasted for more than 3 days. I told her to take 1000mg of vit c every two hours. May 5 we had unprotected sex again. And then we added dongquai and parsley into her self induced menstruation. So in short. She was taking vit c, parsley tea, and dongquai since may 6. Her menstruation came on may 9. but it was a light bleeding, dark red to brown color. May 10 she still had light mens but this time there was clotting. May 11 evening as i am writing this her menstruation is nearly gone. We took three pregnancy tests in a week, spanning from may 5 to may 10. First one got negative and a very faint positive line when you shine a light on the test. And the second and third both got negative tests.