What Does Spotting Followed By Heavy Bleeding After Positive HPT Result Mean?

on the 4th of December I took a pregnancy test it said negative the next day I took another test and it said positive and I was having unprotected sex the same day that I took the positirrtedve pregnancy test I started spotting and it started getting heavier and went on for 7 days so I assumed it was my period. I stopped bleeding on the 11th and did not bleed for a week well today is the 19th and on the 18th I started spotting brown and its mostly when I pee and when I wipe but its just brown spotting can you give me some advice could I be pregnant?