We've all been alone, and we've all been lonely. We usually choose "alone" - a time set apart to pray, reflect, just re-charge. I can remember a time when my kids were quite young when my husband took them all out for the day, and I had the house to myself: glorious!
But lonely? That's an existential horribleness. You can be surrounded by people, even people who love you, and be isolated. And that's where Christ was in these last few hours.
Look around today. Is there someone who seems lonely to you? A young person in your life struggling? An elderly person who maybe appears alone but perhaps is struggling with loneliness? A co-worker or friend who is "out of sorts"? Reach out today, and let them know that there is someone who is willing to keep watch, be a companion, offer comfort.
See, the Lord God is my help; who will prove me wrong?