Hey Megss ~ When I delivered my daughter, I also had a stich or two fall out on their own, and they were also purple. It is kind of frightening because I thought maybe I wouldn't heal properly. I'm sure you're fine as long as you're not in severe pain or experiencing bright red bleeding. Call your doc if you still feel uncomfortable though...you know your body better than anyone. I too had no idea how many stiches I had because I refused to look!
Hope you're getting sleep!