Have you seen the actual records the doctor in question submitted? It sounds to me you are dealing with multiple medical issues that could still significantly interfere with your ability or capacity to sustain employment. As to your disability case, consult with an SSDI attorney right away to determine the merits of your case and appeal as soon as possible. As to suing the doctor, you need to be best informed on what was actually submitted to SSA. Your success in a lawsuit, regardless of what it may be, will revolve around your ability to establish a cause of action and damages flowing from such action. My best to you.