Sorry to hear you have been unwell.
As you know that yu have kidney stones, it is likely that even though you do not feel them moving, they still may move a fraction and cause the show of blood in your tests.
I hope your appointment with the urologist has now come through so that he can do further tests.
Make sure you drink plenty of water 2-3 litres per day. This will help to flush them out if they are not stuck.
wishing you a speedy recovery.