Help is it implantation bleeding ?

so i am 10 days late and i took a test and it was negative but yesterday at night i started to see some brown spots and it's realy realy clear like almost yellow and i never have that color with my period because it's very strong usually . so might it bee implantation bleeding and when should i took a test again ? and by the way i was taking a medication that should start my period preparing for starting first round of clomid but it never came so help , advice any thing