You are definitely NOT alone with having left still thinking it was the truth.
I left 2x still thinking it was the truth. Once in 1967, once in 1984. Both times there was no support groups, internet or ways to find others in the same boat. I was raised a JW from the time I was 3 years old. My Mom and Dad were almost fanatic about it and they went to serve where the need was great in 1958, he became an Elder/congregation servant. He was always shouting at me, pulling me out of bed by my hair, hitting me with a belt etc because I didn't study the bible enough and didn't have enough interest. I hated him and blamed the religion so I plotted to leave the minute I turned 18. I did and then I purposely committed fornication to get DF. I was totally shunned, I had NO friends, I was young and naive. I became a total mess, nightmares, wrong choices. I got married, stopped being wild, had 2 kids and worried Armageddon was coming still, didn't want my kids to die so I went back. I stayed in for 7 years, hated it, finally faded away but still believed it was true. I thought I would rather die than live that lifestyle.
I started drinking, partying and making another mess of my life, live today for tomorrow I will die sort of thing. then about 5 years ago I discovered exjws on the internet and my eyes were opened.
So I spent most of my adult life believing but hating it.....until I found the truth about the truth. What a Huge thing that was for me.
I feel bad for my Dad. He left in 1973, he was a special pioneer, he saw the hypocrisy of the organization. He said he was leaving DA'd himself until they stopped showing favoritism etc to those with money. He still believed it was the truth but he hated the way the organization was hypocritical. He died in 2001 still believing it was the truth. I wish I had found out about the internet exposures before he died so he could have died in peace.
Deceived aka Paula