You have been given a lot of advice by the many posters here, but you will have to make the final decision. Its not an easy decision to make. I know, because 20 years ago I was in a similar situation.
I had served as an elder for almost 10 years before I learned the truth about the "truth" by reading Crisis of Conscience. I didn't resign right away because I thought I could do some good as a "double agent." I even had an "apostate" friend who I kept informed about the local BOE and the latest info from Brooklyn. I had to be careful about our clandestine meetings, making sure I wasn't followed.
During this time I served on several JCs and was able to influence the other members of the committee to be more compassionate toward those who appeared before us. As a result we didn't Df anyone but gave private reproof.
There were also a couple of cases of suspected "apostasy" in the congregation and I was selected to lead the investigation. Here I was able to manipulate the evidence and discredit the witnesses who brought the charges so the investigation led nowhere. Unfortunately there was a sister in the congregation who had become vocal in her criticism of the "Organization." But guess who was on the committee that tried her case? The other members put me in charge of the investigation, and of course I gave her a clean bill of health and no action was taken against her at the time. However, a year after I left another JC was formed and the poor sister was Dfd.
After about 9 months I decided to resign and get on with my life. My "apostate handler" asked me stay on, saying I could do more good on the inside. But I felt that I had done enough and it was time to fade away from the totalitarian Watchtower society and escape to the free world.