A few tips. First, if you really hate nightmares, you can just turn them off in settings in 0.9.
Second, most nightmares are "winnable" and if you do them correctly, they can give you some really good benefits, like 100+ hunger or stamina. Don't have to sleep if you win a nightmare and basically get a second-wind, allowing you to get even more work done before the end of the week for a nice, juicy weekly bonus, which helps your progression.