Hi all.
Just wanted to post on here to give some reassurance to people who test regularly and see their test line gradually becoming lighter as weeks go on. I found this was called 'the hook effect' where the test is overwhelmed by the amount of HCG the farther along you are and your test line becomes fainter than the control.
To test this out my top line is first morning wee at 8 weeks and it is considerably lighter than it has been in the past. The bottom test is diluted with some water and as you can see it is a lot darker! Same urine sample! Hopefully can save some people some worry 
Best wishes to everyone on their journeys x