You are NOT a horrible friend, you are a friend who is feeling horrible. It isn’t easy to feel that way and it does get better, but that wont make you feel any better right now. Just tell yourself that if Hashem is pulling away your crutches, He must believe you have enough balance to take a step on your own. It sounds so cliche to say, “believe in yourself” but it is really the foundation.
I know what worked for me might not work for others, and since you don’t know me you might not be able to accept my words, but I will go out on a limb.
High school was very hard for me for many reasons. A friend and I wrote many poems and shorts stories about anger and depression and about evil adults and boyfriends etc. We lived and breathed our pain, read and wrote about our misery and could see no way out. Over time I found that we were perpetuating that misery. I can read about your pain and bring myself right back down to those places, I can only imagine what is involved in writing them.
Writing about smiles and rainbows isn’t the answer, but writing poems and stories about little sunshowers and small bursts of goodness or happiness that I actually felt or experienced helped surrounded me with those feelings too. The poems about hope perpetuated hope and made the feelings bigger and more alive. They had to be about real moments, not fake ones. But they kept them growing and built bridges for me.
Just a thought, NOT a mussar. Please accept it as support from a friend who gets it.
***two hugs**