Looking for advice please

So I’m 8dpo and my period has came 5 days early. I’m meant to start letrozole on my period but worried if I should start it and say this is my period or skip it incase it’s implantation due to being only 8dpo. I’m not spotting it’s an actual bleed. Should I take a test anyway tomorrow before I take the first pill just to try and be sure it’s a period?