The indicator in this premise is "if" and not "cannot" so the "cannot" serves as "NO". So since "if" indicates sufficient, then it would be LSD -> /Meth and the contrapositive, meth-> /LSD

same!! but I'm thinking of taking it anyway and if need be retaking in January

I understood it as /profits increase-> congestion decrease, there is the "unless" indicator, which means negate either side and make it the sufficient condition. So I negated the "/profits" which just makes it "profits" and got :

profits increase->congestion decrease and was able to add it to the rest of the chain