Pregnancy tests are more of a yes or no test Vs a how long test. Clearblues have some degree of accuracy but so many things can affect them such as time of day, how concentrated your urine is etc! Have a look into the hook effect also!
These tests are just a money grab in my opinion x
Whilst I rationally know these tests are a bit tenuous I have been waiting to see when I get a 3+ and that was only last night when I am supposedly 6+5 but only a scan can properly date you x
Sometimes it can take people to be like 6+ weeks (from start of last period) before they get a 3+ reading.. I wouldn't stress about it