Hello. You just completed "Pending Notification" phase, not the Final phase. You cannot file an appeal until a formal decision has been rendered and award issued. Being" notified" of the "pending decision" does not enable you to file an appeal because technically, until the decision is 'concluded' (i.e. finalized and you received the packet with your award info), it may still be adjusted. Summarily, you have been notified of a pending decision -- "pending" = not final. Once 'final', you will THEN be allowed to appeal. I would recommend you talk with your local VSO so they can guide you with expectations and requirements necessary to prove your case on any point overlooked in the rendered decision you received.
That being said, because your claim is based on PTSD with active substance abuse and schizophrenia, you can expect that should you get an award, the VA will assign a Fiduciary Manager to oversee what money you do get. That entity will likely receive your award and monthly compensation and then issue you amounts held to be 'necessary' for living as opposed to you having 'full access' to all the money. Be prepared for this decision by having a family member at the ready as your appointed financial manager who will regard your wishes and manage your money effectively and honestly. Federal laws have recently overturned the VA's appointing of any member of their choosing and allows the soldier to identify a 'responsible' individual who meets criteria to pay your bills timely and fully, allow you access to your money without you being taken advantage of in your mental state. Also, be aware that because you are considered mentally unstable, you will likely be turned down from legally owning a gun and ever having a CWP, for obvious reasons and in accordance with laws meant to protect all citizens.
Hope this helps. God bless and take care.