Brown discharge

I've just recently had my period and for the paste two day I have had a very very light brownish discharge. It has little to no texture to it, and when it does it almost looks like stringy. It's been so light however no tampon or anything is needed, but like when I wipe after I use the restroom it shows up on my toilet paper. I haven't noticed any odor but this has never happened to me before and it has me concerned. Can anyone tell me what it might be?! Do I need to go to the OBGYN? It's been doing this for two days now going on three. I had birth control but in last month and this is my first period since it's been put in and I'm wondering if it might just be a side effect of that? I have the nexplanon. Please someone help, I'm concerned here. 
Thanks!!!