Attorneys will do what they think you want them to do for you. But they are not mind readers. You have to tell them what you want them to do. As soon as you felt unsupported, you should have asked for an intermission from mediation and had a private discussion with your lawyer.
Does your lawyer know that you are disappointed? First step would be to have a debriefing with your lawyer. Also, you should know that it is normal to have a, "What have I done?" feeling after negotiations. The definition of a good agreement in divorce is that both parties feel like they got a raw deal.
At this point, what you can do is try and renege on agreements you made in mediation. Depending on the framework for mediation you may not even need a justification for doing so or you may need to claim you were inadequately represented.