Side affect of med rises blood pressure and then given one that lowers bp is this safe>?

Hi im 33 weeks pregnant and i was given medication that had a side affect of making blood pressure rise to stop from giving birth too early as i am dilated and contracting. After taking the medication they gave me some more that had the affect of lowering my blood pressure. Is this safe? will i have any side affects and should i worry about any complications? This happened yesterday and i asked the doctor and she said it wont have any affect on baby. Will i have any side affects from this and could it threaten my health?