so I tested myself with home drug test for marijuana and it came out negative, however my ph level was low, what does that mean?


I find that a bit odd.
pH is checked to determine adulteration (urine spiked with additives, bleach, vinegar, etc.) If you didnt do any of those things, the test kit may be defective. In which case, I wouldnt trust the THC result either.
Take another test with a different brand THC test kit.

EDIT: Before completely ruling out a defective test kit, how did you perform the test?