Getting hormones check

So finally my doctor has approved the lab work, actually on 11/25 she did. At the appointment I could have sworn i remember her saying to do it 3 days after my period starts. Well I talked to the nurses because I had my period and was just making sure what day to go and now they're saying it doesn't matter ? What were you told ? 
Not sure if this makes a difference, but I'm getting checked out because I had 3 "chemical pregnancys"