Clear blue digital tests?

Me and my fiancé have been trying to get pregnant since about January, one of my best friends is donating sperm. I've been Taking prenatals, using preseed, soft cups, have a known donor that helps very often. 
  We had taken a break, starting back decided we'd go ahead and buy the clear blue digital tests. I've been testing for a week and I still haven't gotten anything but low. I'm starting to think maybe there's something wrong with me? Idk I just would like to hear if anyone else had similar experience with these tests and if I should be worried or could be trying something different.