- gratitude is very important
Not just existentially for a chance at being, but just muster as much of it as you can for the people around you, for every kindness shared with you, and for the beauty you get to experience. Even for bad shit that teaches you a lesson you can say thank you. It's literally free.
- helping others
If your own shit is fucked, you might get a little humility, space, and grace by thinking about others. Check in on your friends, find an opportunity to volunteer, donate if it's in the cards for you.
- hydrate and get enough sleep
When in doubt, these two might help
- spend some time in nature
It should feel good to do this, so I wouldn't prescribe an amount of time, but at least 30 minutes of touching grass
After you have those four settled, I think it's worthwhile to start thinking about how you put your life together. In my mind, if you reach for things that resonate with you and you pursue it by doing things that you enjoy, you'll maximize your enjoyment, miss out on things that aren't for you, and meet the right people along the way. The consequences of your actions aren't permanent for you, sure, but if you live authentically and kindly, you'll affect others positively so that they'll have a better trip hurdling through space. Being as joyful as possible will have costed you nothing to help and, on the contrary, gotten you as close as possible to having your struggles be worthwhile.
I suppose I just spend less time thinking and more time feeling - smoking life like a loose cigarette from God on a balcony overlooking meaningless and the void. Alan Watts has a very romantic view of being the universe observing itself that never quite landed for me, but you should check out his lectures. They're very entertaining while being existential. Eckhart Tolle is a 
and is a little more self-helpy, but is still a fantastic source of knowledge about ceasing to create your own unhappiness.
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