No, it is not. It appears that occasionally you have an aversion to food but your appetite is doing well. Sometimes, this can be a manifestation of an underlying psychologic problem. You could consider talking to a general physician or a psychologist about the symptoms. Certain signs that suggest psychologic disorders include changes in sleep pattern (difficulty falling asleep, waking up early and having difficulty going back to sleep), irritable or depressed mood, loss of interest in things that were once pleasurable, having thoughts that one is better off dead.