Buy some at home tests through the internet or at Walgren's or Walmart, CVS, etc. Its cheaper on line. That way you can see if you are clean or not. With your smoking pattern and weight you may be a candidate for 30+ days to be clean but every one metabolizes THC at different rates. You have time and its good that you are abstaining. I was in a similiar situation and had 3-4 weeks to clean up. If you test yourself and you are not clean, go on a high fiber diet, take metamucil, do some intense cardio workouts. About 3 days before your test stop working out and veg out. Read up on dillution. There is a lot of great info here so I encourage you to read up on it and do a little homework. Its well worth the investment of time. Good Luck