How would I get over someone I deeply loved?

I never dated this person, never went into a talking stage with them.

But we did go kayaking together, snorkelling together, I laid on his shoulder, I've walked with him to class, flirted and argued with him, went trekking with him, go karting with him, walked on the beach with him. 

He did sort of get over me I guess, I don't know but its most likely

I have never been able to get over this person is there a reason why and is there a way I can escape it and move on?