If i smoke a blunt of skyscraper weed can i pass my drug test in one week?

okay so ive been smoking weed for about a year now.. like almost everyday, about a half gram of reg or sometimes dro.. and my mom got suspicious and decided to drug test me january first and i failed.. today is february 16 and i havent smoked in 4 days (btw even after my drug test i didnt quit, dumb i know).. but its been a while and i know she is going to drug test me again probably pretty soon but this friday night (feb. 18) i was going to smoke a blunt with some friends and that is going to be my last time for a while til i know ive got my trust back.. but anyways i dont know when she is going to drug test me again but im sure it will be soon.. i am 5feet even and weight about 116.. im kinda chunky lol and i know the THC stores in your fat cells so i was wondering how long it would take for me to be able to pass the test if its in the next week or so... and if there is anything i can take or do to help..and please give definate answers and dont just guess.. thanks(: