‘Small’ things can sometimes cause you intense sadness, and this can be described as ‘situational depression’. It isn’t an official diagnosis but an extreme reaction that is commonly brought on by stressful situations.
This can feel like depression but it isn’t. This feeling is caused by a specific stressful event or situation, for example the death of a loved one, the breakdown of a relationship, and school or job worries.
Because this feeling is about a single thing, one way to combat it is through perspective; this situation doesn’t have to stretch into other areas of your life, so remind yourself of all the other things you still can enjoy and appreciate.