I have to agree with above. Sometimes I feel like we lean on motivation too much. Life isn't easy, and we really do have to force ourselves to move forward sometimes, even when we really don't want to. I know that sucks, but at the same time it's a real testament to those who push through especially when it's so brutally hard. There's simply nothing more heroic!

But also, you said all your suggestions were summer activities, which to me sounds like mostly outdoors things. Sometimes anything active can be helpful. Being helpful to others, doing daily chores, writing (especially journaling), listening to music, playing a game, etc. Really, see this as the experimentation phase. This is the time that you get to look for whatever ideas you can of things to do and try them, finding out what you like and don't like. Even try things that you thought you didn't like, often our interests change over time.