I ate 1 weed brownie 5 weeks ago amd have to get a hair test tomorrow.. I am scared that I won't pass, I have never done anything else in my life. I have dark shoulder length hair

The time element and hair color are unimportant. The amount and means of ingestion are what matters.

First small amounts, single and infrequent use, of THC do not show up in hair drug testing and orally ingested THC do not show up on hair testing. That makes you safe from both standpoints.

Ref:
Auwärter, (2010) Hair analysis for Delta9-tetrahydrocannabinolic acid A--new insights into the mechanism of drug incorporation of cannabinoids into hair (http://www.ncbi.nlm.nih.gov/pubmed/20129747). Forensic Sci Int. 2010 Mar 20;196(1-3):10-3. Orally consumed THCA does not show up in hair. This had been preiously noted by Huestis 2007.

Huestis (2007) Cannabinoid Concentrations in Hair from Documented Cannabis Users (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2274831/) Forensic Sci Int. 2007 July 4; 169(2-3): 129–136.

Thank you for putting my nerves at ease, I got so much conflicting information before through the web