I was in a similar kind of situtaion, and things like that always make me paranoid anyways. So I bought a very popular and respected at home hair test. You cut the sample at home following the directions then send it in to be tested at their lab. It only cost like a 100$, but worth the piece of mind. The test is called the PDT-90, there are many sites you can buy it from. I got it here:
www.craigmedical.com
Hope this helps. Btw, if you cut your hair short, no drug is going to show up in your hair provided you stopped taking that drug and it is no longer circulating in your blood stream