Menstrual/Nexplanon Problem?

So about a month ago I got the Nexplanon implant. After about a week or two I started getting really tired and all I wanted to do was sleep. I lost 10 pounds within a week and I'm continuing to loose more. But my main problem is my period. I have a very irregular period and I had my last on in July. And when I do get them, they only last a couple days. I finally got my period this month (December 22nd) and I'm still on it. It's not normal for me to have it this long and it's gotten heavier. I noticed when I was in the shower that the water in the bottom of the tub was a pinkish red. And it freaked me out so badly and now I dont know what to do. Help?!