am I the only one who gets really worried when..

When my boyfriend doesn't reply for hours, I get really worried.. he tends to reply really late like 3 hours after to my message when he is busy.. I just wish he could time to time tell me "still here babe, talk to you later".. but he just leaves me with no replies for hours.. it makes me so anxious, the worse is that he knows i get worried and he doesn't even try to text me at least once to confirm he is ok...