I am glad the meds worked and you are feeling better! A good night's rest can make a big difference in your emotional well being.
Cutting is something people do when they feel so emotionally overwhelmed they do not know how to cope. It does have some self hatred/ self blame components along with it so when you feel like you are angry at yourself, it may seem appealing to hurt yourself. But if your feeling is fleeting, then there is nothing to be concerned about. It's good you brought it up with your therapist so she knows about it. And what she told you is exactly right. It would relieve your pain for a minute then it would be right back, along with the regret that you cut yourself.
Cutting isn't necessarily addictive as much as it becomes a go to option for people who are in pain emotionally. They feel they have no other means to help themselves and relieve the pain so they choose cutting as their first option. The appeal of the immediate temporary pain relief may make it the best option they can choose at the moment.
It sounds like you have conflicting feelings about how to view what happened to you. On one hand, you feel it may not be an ordinary kind of incident and you will not get better because of that. On the other hand, you feel that you have no right to be upset because you are not out of the ordinary with what happened to you. It sounds like you are trying to figure out what are appropriate feelings in response to what you went through. It's very normal to feel that way. Trauma is not usually an every day occurrence. And not everyone reacts the same way to it. It very much depends on your background, your personality and the supports you have in place in your life. There is no appropriate response to something like this. It is all about how you feel. What the others have to say about it is just opinion and some experience speaking. But they have never gone through what you did nor do they know anyone who has had the same experience you did. This is your trauma and your life. As long as you are having some reaction to it and are not burying it, you are doing just fine.
If this ever did happen again, which is so unlikely it can almost be considered impossible, you would handle it. For one, you are older now which means you are experienced with people and circumstances. You learned from what you went through which makes you aware and more alert than you were then. The chances that you would react the same way are not possible either. Your eyes have been opened to what could happen.