In my understanding PTSD is more of a consequence of a tragic event/events that were forced into the psyche, thus causing general lasting mental disturbances. In that case in my opinion and opinions of many psychiatrists, MDMA would be of a biggest help, as it helps to gently reveal your hidden "shadow" self so you can work with it. Ideally working with a friend psychologist who is ok with using psychoactives like MDMA and psychedelics, would be just what you need with PTSD.
On the other hand, if you are simply feeling depressed, low energy, low motivation and anxiety (LOTS of people do nowadays) - it might be due to a general bad "spiritual hygiene" and lack of exercise, poor diet, abuse of GABAergic, opioid and stimulant drugs.
Anxiety, depression and all of these symptoms are there for you to show that there is something unbalanced in your life and it demands your direct attention. Whatever that might be, it is mostly up to you to uncover.
My advice would be to not to rely on drugs at all, and rather understand their purpose of being tools for your own self-discovery and understanding. You can certainly use psychedelics to help you see more but beware of a danger of reality substitution if you do it too often. Also I recommend to learn how to positively connect with people and make friends - this alone will boost your self-esteem levels.
As for shrooms and dosage - I would recommend occasional deep trips (3g+) with prior meditation, mind focusing and setting a positive analytical vibe. Alternatively some people had success microdosing mushrooms - in that case I recommend to pulverize dried product, mix thoroughly and prepare capsules for further easy and somewhat consistent dosing.
All in all, we are all on our own Way. Each one of us, I'm sure, struggles a lot in order to understand ourselves and feel happy.
I hope you find what you're looking for!