What Causes Constipation And Irregular Periods?

Hello, I'm 49 years old and have had very regular periods all my life...until now. I've recently started having a period every 2 weeks. I also hurt more than ever. Also, I'm constipated more and have gained about 10 pounds in the last 2 months. Have any idea what this may be? Doc said I may have fibroid cysts after an exam in the past. My mom died from lymphoma and she also had a tumor removed from her ovaries, so I'm just concerned. I am under a great amount of stress this year with my job.