Talk to Gynecologist on Periods Missed Its 9th Day Pregnancy Test Negative

*اَلسَلامُ عَلَيْكُم وَرَحْمَةُ اَللهِ وَبَرَكاتُهُ‎* I would like to ask for your advice. My period is delayed this month today is the 9th day late and my cycle has reached 39 days. I took a pregnancy test yesterday morning, which was negative. I also do not have any significant pregnancy-related symptoms that I found on the internet. Until last month, my periods were regular usually between 29–31 days. Could there be other reasons for a missed period?

The day before yesterday, while passing stool with some strain, I noticed a small red blood spot in a transparent fluid discharge from the vagina. I am concerned about why this happened.

In addition I have been experiencing lower back pain, which was stronger today. Since yesterday, I have also felt cramps similar to period pain. When I used tissue, I noticed a very small amount of discharge from the vagina — pinkish or brownish in color (not white).

Please help