People can be...complicated, especially when in an emotionally unstable or vulnerable state. Lashing out like that is usually a "knee-jerk" sort of reaction to avoid further harm or complication. Usually a well-established friendship and cautious approach can greatly reduce the risk of that sort of thing, but I said, people can be complicated. If you wish to appeal, apologize for coming off as intrusive and express that you only wished to know what was bothering them in hopes that you could provide some level of assistance. This should diffuse the hostility and create a more neutral ground. However, if you don't feel like you should apologize, and I can understand that stance, simply avoid the situation until your friend feels comfortable enough to be the one to approach you about the issue. Your call, either path is acceptable. Or if you have another idea in mind, go for that. These are just two potential methods that I happened to think of.