What Does Negative OPK Indicate?

I am 25 years old. I stopped taking my Ortho tricyclen lo in April. I finished the pack and had a period as usual. I did not have a period in May. I then had a period on June 2 for about 5 days and then at the end of July for about 5 days. I have used the OPK and they all cam back negative. Am I not ovulating? Could the tests be wrong. How long does it take for someones cycle to get back regular. Should I ask my dr to run tests to make sure wverything is alright?