Don't worry about it, it's OK to go. I do that sort of thing a lot -- depressed and self-destructive one day, fine the next. My T likes to use the OK times to help me figure out how to deal with the poor-coping-mechanism times.

(Because in some ways it's easier to talk about things and figure them out when one is not overwhelmed by difficult emotions.)

My T will say to me, "So, what happened?" I have found sessions at those times to be constructive (and less emotionally fraught).

So, if it were me, I would go.

-Far