What to do if i have unreciprocated feelings of affection towards my friend?

For context I am 15, male and bisexual, my friend is 15, male and straight.

We have been friends for 6 years, and now after realising that i will probably never see him again( he is moving countries) , i have in fact realised that i have feelings for him. Not in physical sexual manner through more of an inherent wish to show him the most love/appreciation.

I don’t wish to make any change towards our friendship. As if i do confess it would probably change the way he sees me, and vice versa.(as he was the first person i came out to, he had suspected that i liked men anyways)

How should i be feeling about this, as a whole?

Should i convey my feelings?

and what do i do?