Why doesn’t he say I miss you back?

We’ve been dating a couple months now and I’ve said three times that I missed him and all he’s sent back was “aww” and I’m not sure if that is a normal thing or if it means he doesn’t actually miss me! When we are together he shows me that he’s close to me he hugs me holds my hand kiss me walk me home and all that but when we are apart and texting he doesn’t say cute things or send emojis and say I miss you too and all that! The texts have reduced the last week or so and I know he can be busy and fall asleep early since he gets up for work at 4 am but I’m wondering why this is happening ! I feel like I have to kinda ask when am I seeing him again and he’ll say when would you like or I’m down to meet up woth you! Anyone else in same situation? Is this a bad thing ? Is it normal? We did have the talk a month ago and he said were dating and responded positively to the boyfriend title