I don’t know what you mean by blue or green bubbles (I use Android, Chomp for SMS, Discord to IM, WhatsApp for the stragglers) but I’ve never met anybody so shallow that they’d give up a friendship over what brand of phone you use. That’s the kinda thing a very childish 13 year old might do.
I think you might need to re-evaluate who you think your friends are, if they’d rather cut off contact with you than receive a slightly different looking text message. That’s incredibly, INCREDIBLY weird.