Why should my anti-hypertensive medication not work as well as it ought?

I spent from 1.30pm yesterday and all of today (MY BIRTHDAY) til 2.30pm in Emergency because I crashed and burned (ie nearly head-ed the wall) on Sunday night. Docs said my pressure is building and it was 145/100 just few minutes ago. They thought it might have been initially due to a prior operation I had at 4m old, but it was not. Docs let me out, fiance most unhappy. I thought some other meds might have interacted with it and that's why I feel shirty. (I want to see my son grow up.) Headaches too, i thought it might be how I am sleeping (ie not 2 pillows). I feel grateful to have seen another BD come and go.