I'm in a similar situation to you re: struggling with my mental health and suicidality and moving from DLA (indefinite) to PIP. I sent my completed forms off a week before you (mid October) and have heard nothing except for a standard text saying 'Thanks for sending us your... form'. My GP has also not been contacted either.
I hope you hear soon. With my case it's very hard to telephone due to my records being marked sensitive (Special Customer Record), and access has to be granted for someone to call me back, which nearly always does not happen.