I am so sorry for ur loss, you speak so highly of her i am sure that she was a wonderful person who is missed by many...
I feel like ur post is speaking to so many very complex issues and please forgive me if any of this is off base... First of all, expressing ur grief/difficulty coping with her loss is in no way taking away from, or making the tragedy of her passing "all about u"... U are just sharing ur thoughts and feelings. Its very obvious u cared deeply for her and her family through the respect that uve shown in ur interaction with her mom... She was a very important person in ur life who's presence drew a depressed 12 yo out of hopelessness; and who maintained contact throughout the years. I am sure the loss u feel is profound... I saw a card once that said, "How lucky i am to have known someone who was so hard to say goodbye to.." And I feel that this may apply to u and your friend as she sounds like such an amazing person and such a blessing to have been in her life for the time that u had her... One thing that i am worried for, is that perhaps u have slipped back into the depression u felt as a 12 year old? "I'd leave behind a legacy of being a sad, disorganised asshole who fucked up everything he ever attempted and wasted way too much time online" It seems as tho u don't c very much good in yourself right now, even though in ur post i hear the words of a good man who genuinely cared for a friend and who is hurting, not a "sad disorganized asshole"... uve mentioned that there are no therapists in your area, which makes it very difficult, but i honestly think that being able to talk to someone would b a very good thing... U say that u ar at the university, many universities have counselors and mental health professionals to speak with at health services. I encourage u to seek their help... I believe that ur life is just as important as hers and though it is a great loss loosing her, i don't feel that it would b any less of a loss if u had taken her place. The depression may b making u feel unworthy and hopeless, but depression always shades our perception to grey... In spite of how the depression is making u feel right now, please know that ur life is important. Sometimes when we become flooded with emotions or are faced with an emotion that we cannot even fathom being able to deal with, we will subconsciously "cope" with the situation in less than ideal ways. Perhaps ur subconscious feels as tho the grief is too much to bear and has instead refused to feel anything... This may at times b helpful in short term situations as it may help u to get through the day, but after a while, i think its important to give urself the space, time and permission to actually feel the feelings... Staying numb forever is probably not very good for your soul... Grief is such a complex emotion, buried within it, there may b anger, sadness, regret, pain and fear... As the other poster said, its ok to feel all of those emotions... Ur not being selfish or wrong, ur heart is just peeling off some of the layers of ur grief... U r strong enough to feel these emotions, they will not break u... Please remember that emotions will not last forever, they ebb and flow, and thats good and healthy... U mentioned not truly knowing her cause of death and i imagine this is a thought that crosses ur mind at times. Sometimes, when we are faced with really difficult circumstances, we cling to understanding things because that gives us a sense of being in control... Is it possible that the desire to understand exactly how she died is springing from feeling out of control?
Perhaps u could ask ur primary care physician if they know of any therapists in the area; or perhaps he might b able to prescribe medicine to u if he feels that u would benefit and u r willing to take medications... i encourage u to find a good social network, even one online, maybe a grief support group. And though u may feel like isolating right now, for most people, its better to b with others (so that they don't get stuck in the trap of their depressed thoughts) Also i encourage u to spend time journaling, sometimes people who have trouble expressing their emotions find it easier to write things out... Sometimes art also help people get to their emotions... Please spend some time cultivating healthy coping skills, even though initially u may have absolutely no desire to do anything, please push urself a little out of ur comfort zone and find somethings to keep ur mind occupied when u r feeling especially down... And perhaps u may want to look into Cognitive Behavioral Therapy. Even if u can't find a therapist, u can order books on the subject online... Im sorry i know that this post has been disorganized and tangential but like the other poster said, there is a point where it gets better... Please be safe, take care and I will keep u in prayer...