did i misscarry?

i contracted a bladder infection last week and am still on antibiotics for it. three weeks before hand my period was really light and only 4 days long, usually it is four days then off one then two more days of light bleeding. i think i started my period on wednesday but it is really ligth again almost to the points it seems to be just spotting. today i had a blood clot about the size of a fifty cent piece then another a couple hours later that was about 3 inches long and the width of a straw. i know that bladder infections are easier to get when you are pregnant and i have also had tender breasts for about 3 weeks now, also a sign of pregnancy but i took 2 pregnancy tests (cheap ones but friends have had accurate results with the product) and they both came back negative. are my symptoms because of my infection or could i have just had a miscarriage?