Hello, how long has this been happening? If this happened a little while after your period, it could be leftover menstrual blood. The leftover menstrual blood will mix in with the cervical fluids and it may seem a little scary. But it is completely normal.
If you have had a Cervical Implantation, like an Intra-Uterine Device or an implantable form of contraceptives, that will also trigger small bleeding during the beginning of the implantation. Afterwards, it will stop your period completely for a little while until it is taken out.
If you have an IUD and you experience vomiting, extreme abdominal pain, heavy bleeding while you are not on your period and you know it is not menstrual blood, visit the doctor very quickly.
Also, if you are sexually active and having strenuous intercourse, or anything that seems a little rough to you, that could be a sign of cervical trauma. And not to scare you, I will give you the symptoms of a ruptured ovarian cyst.
-Abdominal bloating or Swelling.
-Painful bowel movements.
-Pelvic pain before or during the menstrual cycle
-Painful intercourse
-Pain in the lower back or thighs
-Breast tenderness
-Nausea and vomiting.
Death can transpire from a Ruptured Ovarian Cyst. I do not think that the thin blood strands in your discharge is serious, but if you are worried about it or it gets worse, visit a professional Gynecologist. I hope you feel better soon. :)