I'm so glad it's not just me being driven crazy by these tests.
Though I had heard that the "20,000miU/ml" threshold was a misprint and the actual threshold is 2000miU/ml. Have now sent Clearblue an email asking them if it's a misprint or not - will tell you all when they reply!
2000miU/ml isn't an unreasonable level to test for 3+ weeks, plus as other people have mentioned blood level is usually higher than urine level. So just because you haven't got a urine level of 2000, doesn't mean your blood level isn't a lot higher!
I got 2-3wks at 5+0 and 5+2. Am so convinced that I'm going to miscarry, and these results did nothing for my peace of mind! Have now ordered one last batch to do at 6+0. I know getting 3+ doesn't mean I won't miscarry, but it's just some kind of sign that something is going on...