2+ weeks of spotting?

I had missed a birth control pill (Kariva) one day a little over two weeks ago, but I immediately took one once I remembered, then continued with my usual schedule. The last time I had missed a pill, I experienced 2 days of spotting, and all returned to normal. However, I have been spotting for two weeks now (originally light, but has gotten heavier progressively). Is this a cause for concern? Will this eventually subside? Should I still continue taking the pills as normal? How can I stop this abnormal spotting? Should I contact my physician to determine a better birth control method? Thanks in advance for your input.