SWIM recently had to detox from several months of kratom/oxycontin/alcohol/various OTC shit.
Here's everything that helped swim out:
Meditation: this is a skill that is no joke, it can help with whatever is currently bothering you mentally, at any time. All you do is close your eyes, take deep breaths. It helps to cut out all sensory stimuli whatsoever, but with practice you can learn to tune these out on your own. Focus on one spot or close your eyes and imagine that you are focusing on this one spot. Try to maintain this for as long as possible. Breath in and hold your breath for several seconds before exhaling, you will feel the stress leave your body. Focus on your breath and nothing else. Breeaaaaaaaaaaath in......hold it.....exhale.......nothing else matters. One hour of this should leave you feeling nice and calm for while, but if your feeling panicky even as little as 30 seconds can make a big difference.
Tea. If SWIY is the kind of person that needs to have that "something" that you can turn to, try tea. Green tea is the best. SWIM usually likes to keep a filled infuser on hand.