Thank you for your query at DoctorSpring.com
I understand your concern.
Since you have been taking the medicine at a lower dose, throughout the day, it has been ineffective in controlling your BP to say the least.
Moreover, the body gets used to whatever medicines you take. Suddenly, if you take Aten 50 now, you can also end up developing hypotension.
As of now though, your BP is high and there is mild-moderate hypertension.
You need to talk to your physician and tell him about your symptoms. He will again measure your BP, and add a Calcium Channel Blocker like Amolodipine for controlling your BP. It is not an emergency, but it is better you get yourself evaluated once.
I understand people make mistakes sometimes. Please do not worry. From now on, you can take your medicines properly and also avoid drinking as far as possible.
Hope this was helpful,