Not sure what's going on!

Hi everyone, I'm new here and just looking for some advice. I'm on the pill and missed 2 days approx 3 weeks ago. I took a test which came back faint positive a week later but then had pain and started to bleed. So I took one in the evening it was neg. I waited to do another at the end of the week in the morning and again faint pos but still bleeding. Went to gp today and she said the test was neg and it's a chemical miscarriage. Said I should test again on Fri and Mon. Clear blue digital test is neg but took a cheapie after and that was positive again once I got home from the docs. The lines aren't darker or lighter than before but they now appear when I test in the afternoon. 

Has anyone been through this before? Could I be pregnant or are the tests just picking up remaining hcg? Xx