I shared information about my girlfriend's pregnancy and an abortion from a previous relationship with somebody else.
Why did you talk to somebody about their abortions?
You know I was drunk that day. I can not be held responsible for my own words and actions.
Drinking does lower your defenses but you shouldn't have told personal information about your significant other with other people. They will feel betrayed and will no longer trust you.
I couldn't help it.
If that information was told to you in confidence then it was your responsibility not to tell people about it. This was a serious breach of trust on your part, I don't think you should downplay it.