Str8 sec chat
I've actually went through the whole falling in love with your best and straight friend when I was a teenager.
Telling your best friend your falling for them could damage your relationship. If you're sure, tell then how you feel it'll feel much to get it off your chest. It's happened to me so many times that I fall in love with someone who is close to me and doesn't reciprocate my feelings. You could try to tell them and if they are your best friend then they will understand that it isn't something that you can control or maybe like you the same way.
Talk about it only to people who are completely unconnected to the friend, like a therapist or online friends--otherwise it will have a way of getting back to your crush. DO NOT defiantly scratch your initials and theirs in a heart on the wall of a bathroom stall in a public place. *cough*Do not feel ashamed for your feelings for your best (and straight) friend. I know you're thinking that's the last thing you'd want to do and you think you'd ruin the relationship you've already established with them, but if you don't say something you never get the chance to see if it could turn into something better.
I do not think your friend will absolutely hate you and get rid of you from their life.
You have a 50/50 chance with it, either they'll appreciate you being honest with them with how you feel and try something more exclusive with your OR they'll still appreciate your honesty with how you feel but respectfully decline but will continue on wanting to be friends. We get over it, but it hurts like hell while it's happening. the person might feel uncomfortable being around that best friend.
With that, you're not being hurt by much, just know being friends is still a good thing to have. but keeping it to yourself will do no good, so if that's your best friend out their he/she will understand you and will probably give you a helping hand.I just want you to know you don't have to figure this out on your own. Make making them happy platonically the primary goal by being there for them, It'll help your friendship, you'll feel good about helping them, and it's always good to be nice to people.I know this might not be something you want to discuss with your friends or family, but if you join this site you can get free, anonymous support from trained listeners and a huge support community. Apart from that, lots of tissues for tears and a good book for distraction while you're waiting it out.In the worst case scenario you'll need a new best friend but atleast you won't be able to get more attached and face more heartache.