Very large clots very little blood

[Rikijohns]

So to start off, my boyfriend and I had unprotected sex the week that I got a nexplanon implant. About a month and a half ago. Two days ago I had a very light brown discharge come, it was extremely light. Then I experienced heavy cramping. To the point where I had to stop what I was doing. Then yesterday I passed a very round and red mass about the size of a thumbnail. Today I've had some extremely light bleeding and just a few minutes ago passed a mass about two inches by three inches. It was mostly dark red but a dime sized portion of it was an extremely light pink and veiny looking, also more round than the dark part.  I'm not sure if i am miscarrying from a pregnancy that happened right before the implant, or if this could be a side effect of the birth control. I've also had acne, mood swings, loss of appetite, feeling nauseous whenever I eat anything, having trouble sleeping, and extreme anxiety. I am planning on going to the doctor but I wanted some input on what other last think it could be, especially if anyone has similar experiences on the implant. I also should mention that I have had a miscarriage before, but I had more blood along with it last time. Any opinions or advice is appreciated. Thank you.