Long distance relationship

This guy tells me he loves me etc and we have even discussed marriage. Off late there has been a dip in communication because he is too busy and he says he can’t help it when he is tired and falls asleep.
All I ask of him is to call me once a day and even if it’s just for a short span of time. Not too much to ask is it?
Ive been having a bad feeling in my gut about him. Off late I’ve been putting a lot of effort and despite me asking him to just call once a day he does not heed to my need.
Is it worth pursuing such a man or should I just back off and retreat into my shell?