Possible misscarry?

Re

I got my period September 16th and it finished on the 22nd .

(Also got my nexplanon out on September 21st,2017)

Then started super light spotting on the 29th... then brownish blood came out on the 30th, but then later on that day big blood clots started coming out, and alot of bright red blood. It's even going through my tampon and i wear SUPER tampons. Today went to the restroom and alot more blood came out with alot more blood clots....

My and my fiance been having unprotected sex since I got my nexplanon out and hw has been Cumming inside of me. I was looking online and it said possible misscarry... but I don't know... I never had one before can anyone help me out. Also been having super bad cramps, on the 28th I wanted to cry from how intense the cramps were.... help please im so scared. . Also never took a pregnancy test, I didn't think I needed to since I had barley got my nexplanon out