Hello Sailorgurl,
You're right, "what is done is done" you can't take that back, just like you can't un-make a cup of coffee once it's made. Don't go too fast too soon until you are sure that this is the way you want to go, or have to go, as it may have consequences you can't handle or can't fix. Young folks are pretty resilient, and a lot more open to this like this than when we were young so it may not be as bad as you think. Just be more careful in the future, and don't make any rash decisions. May be the thought or prospect of your pending deployment spurred your need to come out to someone and your brother seemed like the safest one to start with.
Personally, I would slow down a little until I've had a chance to discuss this with your therapist . Tuesday is not that far of, be patient, don't rush, and stay in control. You will be in a better position to decide on the course of action you should take after your therapy session, just be patient, what will be will be.
Take care,
Steph