Glitter, it could be that you're just missing the surge. Or it could just be dodgy cheapies! When I get as close to a positive as I think I'm going to get on a cheapie I make sure on my digital tester. And then don't test once I have a positive on that.
Can I please be put down to test on the 26th. My cycles are all over the place so it might change once I know I O'd