positive then negative

today i took a test and it came out positive but very faint you can go to my linespotters post to see how faint anyways, i took another a few hours later on a dollar tree test again and it was negative could this be because it just couldnt detect it since iut was already so faint withg my fmu?

The negative one was most likely faulty. Congrats!

Your urine was probably more concentrated with the first one. Wait a day or two. Or do early morning with a FRER.  

Use your first morning urine it could have been diluted

Yes, your pee can barely read it with FMU so more than likely it was too diluted to pick it up at all the second time.

Good luck   and congrats