help?! Late period negative test

My period is over a week late.. had went to the doctor about 4 days ago and they did a urine test and told me I was not pregnant but had a bladder infection. I still have not gotten my period and my period is always on time except for once when I had a chemical pregnancy.. I have been ttc for a year now. Why else could my period be late? I’m not stressed or anything and the dr was no help at all.