How long will it take for thc to leave my system if i'm a chronic user?

Depends on use.: It depends on how often you use it. If you used it only once it can be detected by blood for 12-24 hours while it is detected in urine from 1-7 days. With regular use it can be detected in blood for 2-7 days and in urine anywhere from 1-100 days even if a heavy user. Age, height, weight, metabolism all are considered factors.

Well over a month: Chronic and heavy Cannabis smokers have been shown to have a mean half-life of urinary detection of THC of 32 days. In one case a chronic heavy user had THC in urine detected 93 days after last exposure. THC is fat soluble and is stored in fat in the body. Release of the THC from fat after cessation of use can take a long long time. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689518/