Is Provera Advisable For Absence In Periods?

I took plan b back on Oct 10th. I had a lighter period with dark blood on Oct 23rd. I have not had my period since. All pregnancy tests I've taken have come back negative. My OB/GYN wants me to take Provera to induce bleeding. After reading up on this drug I've found it has many side effects and usually isn't prescribed for missed periods until amenorrhea is dianosed. I have not seen my OB/GYN in the office, I only spoke with her over the phone. I don't want to take the medication. Is it possible that I might be pregnant and getting false negative results or should I go ahead and take the Provera?