It sounds as though they helped you and gave you community when you really needed it. Now that you have grown beyond the lies and your integrity has forced you to leave, you are left asking "who am I"? It is the same with many New Age groups but not all are set up to be deliberately fraudulent and often many of them do do some good but because of their lack of true foundations, eventually the cracks begin to show.
The 'Core Shamanism' route 'can' (not always) have similar problems because there is no cultural foundation to base it upon. Having to re-learn and distance oneself (can you tell that I am talking about myself here?) from the only 'family' who have given one community, teaching and healing is incredibly difficult.
I remember speaking to one well respected teacher about sweat lodge. She openly admitted that back in the 60's and 70's, there was nobody to teach them. What they learned came from travelling to the USA and learning directly from 1st nation people there. When they returned to Europe, so many wanted to know, to share and to experience. They yearned for this part of their lives which Christianity had taken away from them but who could teach them? So they did what they were lead by Spirit to do then and shared what they had learned. If it was wrong, then they did not know it. What it did do, however, was to start opening the doors of acceptance and perception to people who had, themselves, been stripped of their own nature based spirituality centuries ago, yet who knew in their hearts this was the truth they were seeking.
Lots of mistakes have been made by every person/ethnic group on the planet but somehow this tide is turning and it is people like you and I who have been there and know the difference who can start to look again at who we are so that we don't make those same mistakes twice.
Whatever lead you to that group 11 years ago, you needed to be there. Now that you don't, this major part of knowing who you really are has started to click into place. Try not to be so hard on yourself. Everything around us teaches us - even a gentle wind teaches us not to urinate in that direction, it's all part of some larger purpose and knowing that you are part of that larger purpose is pretty amazing!