Help!

I recently got out of a very serious relationship about 6 months ago with the father of my child. I have had no interest in dating at least not for awhile but i met this guy and he’s amazing. There’s just one small problem...he texts or calls me non stop when I don’t respond right away or assumes I’m mad at him. I’ve never dealt with something like this and he’s very sensitive so I’m careful with what I say. I’m a busy person between working a full time job and taking care of my daughter and can’t be attached to my phone all the time. I have explained this to him multiple times and apparently he doesn’t get it. I don’t want to hurt him but sometimes I just don’t want to talk to anyone all day and I don’t feel like I owe anyone an explanation for that. Does anyone have an advice on how to deal with this?