I think that it might be a good idea to see your doctor. It may be due to pregnancy but I am in belief that is more likely due to that your body is having a hormonal change that is mimicing pregnancy in you, this is a common occurrence. OK, so one reason that I suspect this is that last year at the age of 37 I had my hysterectomy leaving my ovaries in there, I have had no problems since. I chose hysterectomy as my option as my gyno/OB refused to do an Ablation because of two reasons; a) it is not permanent solution and guaranteed that your periods will come back and probably sooner than 5 years, b) your periods will come back and possibly worse than before. Reason for my hysterectomy was due to very heavy bleeding with periods and very painful, which was my whole life. My doctor delivered my child by emergency c-section and did my tubal cauterization right after. After getting my periods back and they were worse than ever I went back to my doctor and we decided on the hysterectomy although researching much less evasive measures which he all declined to do with the above information. I am extremely happy with my hysterectomy and love living with no periods that got into daily living and keeping my ovaries so no HRT ever, also no more pregnancies!
Good luck and hope this can help.
BTW if you are pregnant you need to know ASAP as chances of ectopic pregnancy increases.