Weird things going on

i had my paraguard removed on sept 11th. And I got my AF.on Oct 2nd.. 4 days earlier then I should of.. it lasted 2 heavy days& 1 light dark brown spotting.. then finished.I took it as my period... but today I spotted a few drops of blood. Into the this weird period from the removal.. I know the paraguard is non-hormonal.. took. A test on the 6th bfn.. any info or thinking it could be a cyst. Thx.