Any time we are ill or have an infection, it can indeed make us late. That is a known cause for being late. They tested your urine and didn't find HCG, correct? That is a strong indicator that you are just late and not pregnant, hon. The positive for UTI must have come because they had the bacteria cultured. Anyway, I think it is most likely you are just late at this point. I'd wait a full week and take another test then and then one week after that. If you are pregnant, you'd know by then. They can test your blood as well but you should wait a few weeks for that. By the way, I had a slow thyroid and had long cycles because of that so there are a lot of reasons why it can happen. good luck