What Causes Abnormal Menstrual Bleeding And Irregular Periods?

Hi, im 24. I m not sure if I am having my period with unusual clots or something more serious.. . I had what felt lperiod cramps and Ive been passing a few long fiber like tissues that are not normal compared to my normal blood clots. The best way I can explain it is as if a cotton ball was stretched apart and you can see all the long fine fibers. Almost like very fine hairs. The bleeding is not heavy as of yet..but its been varying between bright reddish pink and just normal red. I do not have a thyroid and am on thyroid replacement medication. My periods are irregular and dont always come every month. Sometimes every other month or less. I did not get my period last month. This had just been happening since this morning.