Heartburn Question

I am 19 and have recently started having constant heart burn. I am not pregnant amd was wondering if anyone has used Nexium to help with their heartburn. I have been taking it for over a week because my doctor gave me a bunch of free samples of it, but I still need to take rolaids or tums occasionally. Is this normal? Cause over all the pain has gone away for the most part except for first thing in the morning, sometimes in the afternoon and at night right after dinner.