disapearing line

hello, i had a miscarriage about 6 weeks ago i done a clear blue test which was negative, recently i done a test from pound and and 2nd line came up on the test but then disapeared, so i brought two more from wilkos one had a faint line i done the other one a few hours later which was negative? some im abit confused to wether this is hormone levels after a missacariage? please reply thanks