The Hook Effect?

OK, so I know I'm not supposed to keep taking HPTs once I've been confirmed pregnant (I'm currently 7.5 weeks today, and my hubby and I have been TTC for 3 years). However, curiosity got the best of me this morning. 😶 To my dismay, my test line was MUCH lighter than a test line from a hpt taken 2 weeks ago. Needless to say, I began freaking out. After doing a little research, apparently this is a common occurrence and is called "The Hook Effect". The hpt is an antibody test that measures HCG in the urine; if there is a large amount of HCG present, the test gets overwhelmed and actually gives a faint line. If you dilute your urine 50:50, you'll actually get a dark line (tested and confirmed). I've also read this may be common if you're carrying multiples. My first ultrasound is in 3 days. Any other mamas experience this?