Stefano,
I totally get how people give you a ''Push'' to go and do things that you ,when depressed,are totally not into.Sometimes you just cant because you need time to take care of yourself.Then to make matters worse you feel guilty for not going or doing the activity.
However, you might try to do something to get out as "retreating" or "hiding" at home kinda defeats the attempt to get better.Sometimes,even when you force yourself to go,it turns out to be not so bad after all.
Take care