Journaling About Painful Moments

Things got overwhelming yesterday, so I called the hotline. I keep going over a nasty fallout I had with a friend last summer, and it's left me isolating myself and with very low self esteem. Aside from bringing it up to a listener on this site, I haven't really talked about it with anyone, at least how it affected me.The person from the hotline recommended I journal about it to see if it will help me move on from the incident.

I started journaling about it today and it's a lot harder than I expected. The more I write, the angrier I get when I remember it. I know that working through it and confronting my feelings about it will help, but my anger is keeping me from continuing. Is this progress or am I going about this the wrong way?