Also keep a mood diary - then you can actually show them the tracking of your mood, which will help...
FWIW I've had an assessment for therapy, then a few months later a "holding group therapy" where you don't talk about your own issues, it's purely biological info etc and grounding exercises and then told the actual wait to see a 1:1 therapist is expected to be years. So I do understand, but honestly I think you need to work on things to help yourself - grounding, breathing exercises, mindfulness, meditation etc and get yourself in the best place possible.. That was the advice I was given....