I drink over a gallon of water a day...

Hi ladies. I had a positive pregnancy test at 3w4d and have been slowly having the onset of pregnancy symptoms but my only concern is that if I test using an HCG strip the lines are not getting darker. I should be 5w1d today and I tested first thing and there was barely a line. I do drink over 128 oz of water daily. Does this sound like it could have been a chemical pregnancy or possibly a miscarriage? I’ve had no bleeding or cramps. Just vvvfl on tests. Thank you for your advice. I will get in to have my HCG levels checked on Monday was just curious on others experiences.