I’ve experienced this before — falling into a rut, becoming depressed and having extraordinary difficulty getting back up. It’s like a motivation off-switch.
Talk therapy is good. Try to find a therapist that you can trust.
Don’t be afraid of anti-depressants, especially for something likely to be shorter term like this. They don’t change your personality (although you might put on 3 to 5 lbs).
Are you being treated for ADHD? Some people with ADHD find that their depression goes away when they take psychostimulants or practice CBT to manage their symptoms.