Sharing Our Innermost Thoughts

So this guy I’m in a casual relationship with is my best friend. Sometimes I don’t know if I did the right thing cause at the start I thought that cause I didn’t want anything serious, this felt right and it felt like we could keep our friendship intact even if the casual relationship ended. I’m totally okay with that concept too. The ONLY thing I told him was to communicate with me. He readily agreed to it and up until recently, we communicated our things and emotions out pretty well. But off late, he’s been busy and I’ve been busy so the communication has decreased to once a day or once in two days. I’m a lil overwhelmed by that although I completely understand that he has work but at the same time, I don’t know why this situation questions his friendship with me. Like if I was his best friend, he’d still make time to talk to me. I’m not saying update every moment of your life but in a day, at least ask me how my day was or when I ask you something, I expect a decent appropriate answer and not answers that are half-hearted or unbothered. Something you’d text to a stranger. Cause although I’m busy too, I text him back or make an effort to talk to him. It’s sorta been overwhelming at the moment. Sometimes I feel sad that although I trust him completely and don’t suspect him of cheating and all, I still feel sad that he doesn’t feel like sharing stuff about his day or about him anymore. It feels like I’m repeating my cycle of going for people who aren’t actually interested in me or maybe I’m the reason for this change in the other person. Maybe I got boring or maybe I’m too dumb for him or maybe I’m not as interesting I was at the start when we were just friends. I know that I don’t love him as a boyfriend or anything but I love him as my best friend, I don’t even know if that makes sense. So, all I’m sad about is that my best friend doesn’t really have the time or doesn’t make time to talk to me even like once a day. I miss my best friend. I miss talking to him. Miss being myself. This overwhelming feeling is just eeeek. Don’t wanna feel this way. As much as the thought that " I don’t NEED anyone" or that " I don’t chase" is there, I still want him to be there for me.