What Causes Spotting And Throbbing Sensation In Breasts?

I miscarried back in October and I just had my period the 18 of November. I started having red tinge blood on the 3-4 of January and it stopped for a day came back again and it looked like bloody tissue after I peed. I then stopped again and I just went and peed again and blood covered the toilet paper but before I wiped I'd noticed bloody tissue again. My boobs are throbbing so I thought I may be pregnant again but not sure what is makine me or why I'm bleeding. I'm not cramping or anything like that either.