Mindfulness practice & marijuana

I've been meditating for a little over a year now, quite regularly, though there were a couple months when my practice fell off. Throughout this year of mindfulness practice, I have been tempted with the consumption of marijuana more than once (in fact, innumerable times, since my siblings regularly smoke). I have noticed that the two activities--mindfulness practice and smoking pot--do not mesh well at all. I always end up feeling overwhelming guilt after smoking, mainly because it makes practicing mindfulness more difficult. It used to be impossible for me to meditate after coming down from a high, but it isn't impossible--just very different and very difficult; I feel as though no progress is being made when this happens.

I've set goals for myself several times, namely (and most recently) vowing to remain sober for this whole lunar cycle (to honor the moon within my life; I've an affinity for the moon). But that goal has been shattered, as I didn't honor my own commitment to it, and ended up smoking with my brother. I feel really awful about this, like my mental chatter will not stop reminding me of my folly.

Has anything like this ever happened to anyone else? How did you deal with the feelings and what steps did you take to overcome the problem?

Many thanks, friends. 🙏