So I only have a few close friends at my university. Im an introverted musician who is very picky about friends, I know within 30 seconds if someone will end up a close friend of mine and its really based off of music. My closest friends are my bandmates. Anyhow, there has been alot fo situations where I get left out of plans and I take it very personally even though its never a personal issue but rather a situational one. I take it personally because I dont have an abundance of friends and when one bails or leaves me out of plans I always feel a bit hurt. This weekend I was planning on travelling to a close by university for St. Patty's day and I knew that two of my friends were going too. I assumed that they would be taking the train and when I asked both of them what time train they are taking they said "Im driving". As soon as I heard that I thought "Those assholes, are obviously driving together and didnt think to include me in the plans"

And that was exactly what happened. It wasnt a personal thing, rather they happened to be talking about it a week ago with another friend of mine and decided to rent a car together. I would think that they would have thought "Oh I think Hershiekopper is also going, lets message him to see if he wants a spot" cause thats what I would have done but then again thats only because I dont have abundance mentality when it comes to friends as I only have like 5 close friends here. So because of that I know its not personal but how do I approach reacting to these types of situations or not reacting. All I said to my friend was "not nice for you guys to not include me" to which he responded basically saying "Its not personal, we just happened to make plans and Im sorry you feel that way" Which is fucking annoying cause this particular friend will never admit to his faults. I Replied with what may be some blue pill shit but I honestly don't care. This friend is probably my best friend at this point and not a girl im trying to fuck lol so I rather him understand that this pissed me off. I responded "Oh Fuck off with the “I’m sorry you feel,” how about “Im sorry I never gave a thought about including you in these plans”. You honestly need your ego checked. I’ll see you there" He eventually responded with an apology to which I replied simply "Its Alright man, Don't sweat it" Cause all I wanted was an apology so that he'd be conscious to at least consider including me in future plans where i'm not present in when they are created. Anyhow, What would be a Red Pill approach to being excluded?