You might try explaining in a letter, or ask if they would meet you for a talk/lunch, the worst that can happen is that they say no and/or are not able to do this. You just won't know until you try. At least you will have done what is good for you, and you will know that you did do your best to make amends. When you were so ill, you were out of control, but now you have choices. Even just a card...a 'sorry' with a note...
Sounds like you need to reach out for your own peace of mind. (((best))) It is a brave action.