once you start down hash oil highway there is no return haha, weed won't work anymore.
Since everyone else is ripping you a new one, and I've been in this situation before, I'll help you out as best I can. Of course your parents are different than mine, but I was threatened all throughout high school with the whole drug testing and rehab gig if I got caught with weed one more time. This was just a never ending cycle, cause in reality both my parents understood that weed wasn't really detrimental to me. I did fine in HS, got good grades, and went to a good university (CU). I stayed out of trouble with the law for the most part, and never actually legally got caught with weed. It was when my parents found $800 in cash and my scale that they sat down and gave me the HEAVY talk.
It's really the dealing you have to stay away from. It makes your habit look 10x worse to them. Obviously I understand you just want to smoke for free, as did I, along with the thousands of high schoolers in america that sell. But when it all comes down to it, they're looking out for you. Getting caught with pre weighed bags and a scale by an officer is far worse than getting caught by your parents, trust me.
You have to gain their trust back. Offer for them to drug test you monthly for as long as they see fit. Again I don't know your parents, but mine never actually did. It was a trust thing. I didn't smoke for a few months, and they never tested me. After awhile I began smoking again, and now can do so freely in my room with my parents consent.
Act remorseful (even though we aren't) and agree with your parents about the whole situation. Explain to them that it was a fun activity that you can give up if that means staying at home and not going to rehab. (bring up the drug testing).
Hope that helped just a little bit, and good luck.