C. writes: I have a mental illness and my friend was the only one who knew about it and my only support in dark times. We used to share everything and she was my reason for happiness. But we had a huge fight recently and we both said some things that we shouldn't have and stopped talking to each other. I, after a few weeks, thought of taking the first step and contacted her and apologized. But she didn't accept my apology. She said she was hurt beyond repair and that she never wants to have that friendship with me anymore.
Now I know that we both said some things that hurt each other, but I am feeling guilty that I hurt her. Even though she hurt me too and never apoligised, I still don't care and still want her back in my life. I hurt more not from what she said to me, but from what I said to her as I feel I shouldn't have hurt another human being, let alone my best friend. I am trying to forget about it but these thoughts capture my mind every passing moment of day and night and I can't help but cry over how I hurt my best friend and regret it every second of my life.
As I’m sure you know, the past is not under our control, so dwelling on your mistakes is not going to be helpful, and in fact it will simply make you feel more miserable. Perhaps you feel you deserve this, because you have hurt your friend. However, a sensible approach to justice is based not on retribution, but on reparation.
Except, of course, that sometimes the damaged party does not accept our attempts at reparation, as you have unfortunately found out. Again, the dichotomy of control comes into play here:
“Some things are within our power, while others are not. Within our power are opinion, motivation, desire, aversion, and, in a word, whatever is of our own doing; not within our power are our body, our property, reputation, office, and, in a word, whatever is not of our own doing.” (Enchiridion I.1)
Your friend’s opinion of you, or her willingness to resume your relationship, is quite simply not in your power, so you should let it go. This is not, obviously, a counsel to take the incident lightly. After all, you lost the affection of a very important person in your life. It is, rather, advice to learn from your experience, move on, and make sure you don’t make the same mistake again, if Fortuna will be kind enough with gifting you with another deep friendship like that one.
For the Stoics friends were very important, just as for Aristotle and the Epicureans:
“If you consider any man a friend whom you do not trust as you trust yourself, you are mightily mistaken and you do not sufficiently understand what true friendship means.” (Seneca, Letters III.2)
But they also insisted that the wise person can be self-sufficient, if the situation requires it:
“In this sense the wise person is self-sufficient, that they can do without friends, not that they desire to do without them. When I say ‘can,’ I mean this: they endure the loss of a friend with equanimity.” (Letters, IX.5)
All the more so if you were yourself the partial cause of such loss.
The above, however, needs to be considered within the context of your mental illness. You do not specify what illness you suffer from, but I would remind you that Stoicism is a philosophy of life, not a type of psychotherapy. It is, however, related to cognitive behavioral therapy, which was inspired by Stoic exercises and which is one of the best, empirically supported types of psychotherapies. My City College colleague Lou Marinoff, author of Plato, not Prozac! writes in the introduction to that book that, despite the provocative title, sometimes one does need medication, or at any rate professional counsel, in order to bring one’s mind back to a functional state. But once that is achieved, one’s problems still remains, and that is were philosophy is effective, as “therapy for the sane.”
My suggestion, therefore, is to adopt a two-pronged strategy. On the one hand, if you have not done so already, seek the professional help of a CBT or similar practitioner. On the other hand, keep reflecting on what Epictetus and Seneca have to say here, and try to internalize their teachings. Your friend may be gone forever from your life, and you may have made a huge mistake. But your life still needs to be lived, and can be lived well by learning and improving. Your goal, like that of everyone who practices Stoicism, is not to become perfect, just to become better than yesterday.