Weird period

Angel
So I got a shot back in May and well whenever I was suppose to start my period I was a little late and I  started the 6th of this month and I'm still bleeding. It's not a normal cycle for me I'm not really even bleeding i can only see the blood when I whipe it does come out on my under wear or even little pantie liners I wear. it's mostly a dark color (old blood) but sometimes it fresh. Id  like to know if this is normal?