Is it normal to talk with him like this?

So, as I entered my first year of high school last fall, I was introduced to my brothers friends, all seniors. I became quiet close to this group and especially to one certain guy. He became my best friend, the first person I came to trust more than anyone else in the world in years, a month or two ago.

So this last week, I'd been having terrible nightmares and I came to him about it and he spent the last week staying up all night texting me. After a couple nights, I'd been able to sleep through the night, but we'd still text each other. I think around Tuesday I had called him 'love' (I had been watching a British show and it was in my head) since then, he's asked if he can call me love and does it all the time. He's also always telling me he loves me and how much I mean to him and how no one makes him feel more loved, and I feel the exact same way towards him so I tell him the same. It's quite cute of him, he tells me I'm sweet and the best person he knows, and he'll even fight with me saying he loves me more ^^

is it normal to be talking like this with my best friend? The main reason I'm asking is because a couple months ago I had developed a crush on him that just grew and grew to the point were I had to tell him, and when I did he explained how he couldn't feel the same towards me because he saw me like a little sister. That was a month ago. I'm sitting here right now looking at a text from him that reads "As do I love I love you so much I cant wait to see you tomorrow love <3 ^^"

IIN???!?!?!