I'm told the effect of BP meds lasts 24 hours so it shouldn't make too much difference what time you take them, as long as it's not too close together, so the same time every day. I never have felt headachy or dizzy with the Ramipril, but my son did. He was put onto BP meds while taking steroids for sarcoidosis. The steroids have been stopped now, but he is still on the BP meds, but was taken off of the Ramipril because he felt it was dropping his BP too low. He now has a different one.
The thing is, there is a difference in reaction even between myself and my son. No two people are the same. The effect shouldn't be immediate though and you would probably be aware of feeling shaky or weak if it was to cause a serious drop in your BP. At the level you are prescribed, it shouldn't disable you.