Fainter line! :( 4 weeks 3 days

Just wondering people’s experiences with pregnancy tests. I’m supposedly 4 weeks and 3 days and yesterday I tested with FMU and got 2-3 weeks on digital. Today I tested when I got home from camping after drinking about 1 L or more of fluid and got 1-2 weeks :(! I’m concerned I’m going to miscarry :(! Anyone else had this experience?? I’ve had no bleeding but cramping quite a bit. Please help