This chart may help. Looks like less than 120 over 80 is within the normal range.
heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/Understanding-Blood-Pressure-Readings_UCM_301764_Article.jsp
Were you well hydrated? If you get dehydrated on blood pressure meds your blood pressure will drop and you may experience dizziness. For a long time I thought I was keeping myself hydrated enough and then started taking blood pressure meds. Blood pressure went way low and I thought I was going to pass out. Turned out I hadn’t been hydrating enough.
That said, not all blood pressure meds work well for all people. My original blood pressure meds caused an allergic reaction after a few weeks. My current medication was not lowering it enough and dosage had to be adjusted. Sometimes, it’s trial and error to find what works for you. If you notice something wrong call the doc. If you cannot get the doc on the phone and you believe your problem to be serious then go to the ER or nearest open Urgent Care center.