i’m really stressed right now because i'm feeling negatively towards a friend who may be my fp?? (i'm not sure whether or not i consider him a fp in bpd terms but he's definitely still my favorite PERSON either way)

i've never had any kind of conflict with him before and we've been very close for 2 years now. i think it started because he mentioned a friend he has that has feelings for him. i don't even know if it's reciprocated or not but this made me so upset and i don't even LIKE him romantically. it's just seeing someone who has the potential to get closer to him than i am that's setting me off. 

ever since he mentioned this friend, i've had issues that i didn't have before. for example, he has always playfully made fun of me. it's never rude, it's always been a lighthearted thing that i've never had a problem with. but right now it's really hurting me. he jokingly made fun of me and i lashed out and said something mean but i unsent it before he saw the message. i have never ever lashed out at him before. i don't typically lash out ( i think i have quiet bpd) so this is making me scared. i don't want to ruin our friendship. he is so important to me and we talk every day so i cannot stand to have this tension. i'm worried that now that i'm suddenly upset with things he's doing and saying (it's more than just the teasing) that our friendship will never be the same again. i'm so scared. 

i can't believe it's because someone is showing romantic interest in him. why would i get upset about this when i don't like him like that? it's so embarrassing.