I am on my period. A wierd blood clog came out with a string attach to it. I do not wear tampons?

PROBABLY NORMAL. During a normal monthly menses (a period) a woman sloughs off the endometrial (uterus) lining. Blood, small clots and other debris are normal. Another possibility is a very early pregnancy/miscarriage which are very common and usually go unnoticed. A preganancy test may still test positive in some cases.