Ian,
I think you have taken a good step in the right direction. I would just get to work on your financial plan and see if you can make some progress getting out of debt.
That way you will have something to show for yourself when you get in touch with your girlfriend.
If you feel you cannot wait that long to talk to her, then I would let her know what you are doing to get yourself on the right track,
and then say you are sorry a few million times over.

If you guys are destined to be together, then you will manage this bump in the relationship.
Long term relationships face many hurdles - and finances are one of the more common issues in a relationship.
Now that the cat is out of the bag, I hope that you two will have a much more honest and open relationship - If things can work out, I am sure you will enjoy being much more honest with her. Like I said, if she loves you for the you that you really are - then this is just a bump in the road for you two to solve together.
If you felt you had to woo her with money because deep down she is pretty materialistic and not into guys who happen to be broke - then you might lose her, but I wouldn't want somebody that superficial for my wife, that's for sure.

I think you will make out fine with your finances - and the good news may be that you got yourself into this crisis situation early - so now you have the rest of your life to have good spending habits!
Good luck to you.
Victor