Today (Friday) the Gospel was from St Luke 22, Jesus praying in Gethsemane. Something went wrong with the recording, so I'll just recap.
Why did the disciples fall asleep? For sorrow. But after the resurrection, they never so sorrowed. Hence their knowledge of the resurrection changed things for them. After the resurrection there was no betrayal, no denial, no flight in the face of danger. There was only unflinching courage, in persecution, and even unto death.
So let the knowledge of the resurrection bolster your own prayers in the midst of challenges, trials, and sorrows. For this knowledge changes everything. It means Christ was victorious in all his trials, which were for our redemption. None of it was in vain; nor, therefore, are any of your struggles in vain.