positive test after miscarriage

it's been 16 days since my miscarriage, ultrasound showed everything came out. Had sex a few times since, first time being on the 21st- 2 days after no more bleeding- and 3 times since. last week for 2 days I had pinkish brown spotting/discharge. well today I took a test and it was a faint positive. how likely would it be that I am pregnant already? I read you can test 10 days after having sex and get a positive- it's been about 11 days and I know you are very fertile after having a miscarriage. no rude comments please