I would be very hurt if I were your girlfriend and you didn't share
this information, especially as you are still actively taking medication
to deal with it.
I think carrying the burden of not telling her would be much heavier
than coming clean as well.
A person has a right to know these things before linking their life
to yours legally and emotionally, and especially before having any kids
if those are in the picture down the road.
I also agree with above that you should not be drinking in any amount.
It's a slippery slope, and easy to tumble down just when things are
looking great.