Lighter tests

I stopped testing a week ago because I got a dye stealer and wanted to make sure they were progressing. Betas looked grest also. Today was my first OB appt, and they said the line was very faint. I have drank a lot of fluids and peed several times today already. Could this cause that at this stage (5w3d i think) or am I more than likely going to miscarry?