Seriously Flare....
No... I'm sorry dear. Some of us have lived and learned, been treated like poo poo by some, and been treated like a true friend by others... and No, your behaviour was not the tiniest little sceric reminiscent of the latter. I'm not moving from this point until I'm certain you understand and accept it.
Yes.... immature feelings can indeed be detrimental, thats why growing up involves learning to cultivate self perception and self control.
Please take time to think over even more carefully the way YOU would have felt in this scenario. Your very best friend in the world has passed away, the one who never made a selfish choice like so many other friends do. You turn to your remaining friends and first share a miniscule portion of your grief with them, then later try to celebrate the happy moments with them.... and then what happens?
This step is sometimes necessary to develop empathy and compassion for others, surprisingly enough, these do not often appear all on their own. You also have to try to have an open mind when it comes to an issue, and not throw it into a neatly labeled box that you've already discarded as insignifigant.
Such as a horse, and the amount of closeness someone can experience with such a friend and partner.
Such as the value of a truly sincere apology that takes full responsibility on the bearer. It may or may not help you in this instance, but you'll likely find in the future that such a contrite apology will have others making the excuses for you to themselves.