Has anyone had issues with tests being positive and then negative and then positive again? What was the outcome for you?

6 days ago I had positive tests, 3 days ago they were darker and yesterday and today have gotten lighter. This morning my strip tests were completely negative not even a shadow, I didn’t drink more etc. tonight they are positive again. I have brown stringy discharge and had pain and a fever earlier which I thought was the start of a miscarriage but nothing now. Has anyone had this issue before? I’ve drank more water today since the negatives so the negative ones were more concentrated and held longer than the ones I’ve done tonight. These are the tests from tonight and I should be 4+1 I’m so confused