Ciaraaa1,
Lubrication is a physical response to a psychological state. Once a person is sexually aroused, then lubrication usually occurs, getting the physical apparatus ready for the physical act of sexual intercourse.
Alcohol inhibits a lot of things psychological. So, if you had consumed a lot of alcohol, it is possible that is the reason. Expecially if you have no problems when you have not been consuming alcohol.
You might want to back off on the amount you are drinking, and see what happens.
Good luck.