Ladies help!?

Sorry about the length ahead..

I wasn’t sure which group to post this in but I figure I could get help here, I’m on the nexplanon implant so I’m not really sure of when I should get my period, (I had it re inserted in March if that helps) and last week I had some bleeding but not like a real period like I would usually have, but this week my nipples are just killing me, like even the slightest touch or graze just hurts, I’m only concerned cause this has never happened before, my boyfriend and I don’t use condoms- don’t know if that could be a factor but I really don’t know what it could be, google is no help lol no shock there. But if anyone has experienced this what should I do, or just suggestions maybe?