just wondering

has anyone had to take nifedipine to keep labor off if so how long did it work i started having contractions 3min apart and dilating and thinning on fri so they gave me mag till the contractions stoped and now have me taking this medicine to keep the contractions down they let me go home Sunday but today i have started cramping again and having contractions not to close together though but me and the doctor are hoping i make it till next wed when i will be 34weeks