I have had my gallbladder removed about 3 yrs ago. I since have been diagnosed with type 3 sphincter of odi dysfunction. I take 75 mg amtriptaline every night for over a year. I have always had a regular cycle and i am not 6 days late. I have taken home test that show negative. I plan to talk to my dr but it may take a few weeks for an appt. Can a spike in amylase/lipase levals or my meds cause a missed period?