almost 30 days clean and I smoked, I am back to day 1 of clean out?!

So I have been unemployed for some time and have been making a strong effort to not smoke.
I didn't quit smoking because I don't want to smoke. it's because I know I need to do the right thing and be ready to pass a drug test at any time. So I actually had made it to over 45 days clean and decided I was sick of not smoking and went and got forty, I knew this would start me back at day 1 for cleaning out my system. After that I held strong and did not smoke anything for 22 days (I know, almost to 30!!!) but today my friend called and offered to stop by and smoke a bowl with me. I thought screw it cuz its free and did, then after I smoked I started thinking and was wondering... If you clean your system completely, smoke an eighth and then don't use for 22 days, but smoke a bowl just past the 3 week mark does this start your 22 day clean count back to day 1, or will it maybe just make it to where it will take a week or 2 to clean out instead of 8 more days? I know no one can say for sure but just curious what affect you think 1 bowl would have on an almost clean system?!