Hello there,
Not sure if the drink would have affected your recall, not much of an energy drinker myself since I've heard pretty bad things about them. As for your attempt, it didn't sound like you did anything wrong. SP differs from person to person. The main advice I can give you is to make sure you are comfortable and relaxed when you are trying to WILD. Also, look at this experience as a positive one since you were able to hit SP. It means that you are that closer to a LD. My only experience came yesterday where I was just lying on the couch comfortable, relaxed and a bit sleep deprived(practicing CAT at the moment) which is when I had a dream, woke up and then had SP, so close to a dream as well. Anyways, you are on the right track, just keep on trying, you'll eventually get there