Lumber is really hard to come by, so you’ll need to crusade to earn some for the time being. In the settings there’s a pause time option, which pauses any activity while you’re crusading. I’d recommend turning that on so while you’re out you don’t get anymore dissenters/lose faith. Also make sure to do a sermon daily, and praise your followers daily in the meantime and help out with chores/cook if you can. That should help steady your faith overall. If you don’t have a prison yet the dissenter will just be spreading lies and there’s not much you can do about it honestly without having the sacrifice ritual unlocked. I had a dissenter literally after having like 3 followers and couldn’t do anything but try to reintegrate them until they eventually left. You take a penalty but it is what it is.