“Can I be pregnant?”

I had my first sexual intercourse 8 months ago and then I put on implanon. Before the implanon took effect, penetration had already taken place. Now after 8 months, I'm very tired all the time and I don't do anything, very sleepy, a lot of headaches, mild nausea, very, very hungry that nothing satiates me, a lot of back pain, cramps, I gained weight and I'm also swollen. I've been menstruating for a month with brown blood and twice something black came out. I don't know if it was a placenta or a clot, my breasts swelled too. Can it be silent pregnancy?