Not sure if it belongs to philosophy, theology or to psychology but let's try. How to stay motivated to do your best and to be very productive on a daily basis when you keep thinking that we people are not exceptional, we are just one of the random species living on earth and the sun is going to explode one day. Yes that's not very positive thoughts Jims Carrey Speech At The Golden Globe Awards 2016 style. But really how to shift the mindset that it's all meaningful? how to regain motivation to stay hungry? falling in true love?

One idea would be that no matter what you think people will keep living and suffering so you can create a meaning in your life by working to lower some peoples suffering or/and increasing their joy. Like in a Groundhog Day movie. What if you play poker for a living with this mindset? Donating some of your winnings I guess. Any other ideas?

Sounds like religion/spirituality would do you some good. It can help turn that gloom to hope while providing you with a sense of purpose.

Become an undertaker.