Masturbated and now discharge and pain

I masturbated last night with a perfume bottle and it was great. I had some weird brown discharge on the bottle when I was done. The next morning when I woke up, I had a lot of brown discharge and cramp like pains. I cleaned up and went out again and when I got home there was even more discharge but it was much darker brown than this morning. Did I do something? It's definitely not my period. I got off my period 2 weeks ago. But I am also on birth control. The nexplanon. but my period has been pretty normal lately. Just need some advice and other thoughts from you ladies! 🙂