Nothing is wrong. It's normal. It's just that the blood has dried up a bit and has turned brown and that it is stringy.
Brown discharge is old blood coming out and usually is at the beginning or end of a normal period. Have you had your periods for very long and how old are you? You may want to get on birth control to regulate your periods. I started my period when I was very young and was irregular for years before I got on birth control. It was the best decision I ever made. Not only did it regulate me but I would also know when I would have my period so I could plan activities around it. I would not be worried about the discharge unless they are unusually smelly or have puss or anything puss like about them. Best wishes, Sissie