I've never been much of a morning person so I can find it easy to imagine a guy could be too busy to call his girlfriend when he climbs out of bed in a rush to get to work. The big question obviously is whether or not he wakes up next to another woman every morning because that could be another reason why a guy doesn't call in the mornings.
Now if he works a late shift and is away from home every night when he calls you, that should ring warning bells. But if he is calling you from home and you know he doesn't live with anyone else (in other words, you know he doesn't have another partner), I think you should give him the benefit of the doubt.
Whether or not he loves you yet or is still getting to know you and is uncertain how he really feels, I can't say. I have, however, written another article that gives you a heap of clues when trying to figure out how a guy feels about you. https://pairedlife.com/dating/How-Do-You-Know-A-Gu...
Take a look and see if it helps clear things up for you.