From our earliest years people are conditioned to see the weekend as R & R time ,and many people are having fun , I have however noticed that weekends can be unsettling for two reasons 1. is the almost universal lack of support services on weekends even if you don't use them or need them per say , having them available tends to make people "calmer" and 2. Your not having a good time during the week let alone on weekends when people are traditionaly more social .

The other thing that I see is in many cases weekends cause family and friends to want to engage more with depressed people ( who in many cases don't want the interaction) same thing applies to holidays it just drives the depression into you deeper , but unless a person has dealt with deppresion they dont understand the disconnect caused by pressuring people "to feel better" or " lighten up" ,because it's not that easy .