Lesser evil?

I'm having a rough time staying sober rn even though i want to and have to (i need to prove sobriety for a DBT ward stay in a few weeks) I stopped smoking cigarettes a few months ago but I think about starting again since it would help me stay off weed. I really don't know... What of those 2 is the lesser evil? I mean staying away from both is the goal long term but rn i'm struggling way too much. Like sleepless nights, mental breakdowns, not being able to eat and everything... What's your take?

Thx in advance, have a good one. And if you're struggling too: you ain't in this alone! Check out NA, they helped me a lot.