When Is Safe Period For Unprotected Sex After Using Trigestrel?

Hi, I took a break from Trigestrel for a month and now I am back on it. I started using the pill the second day in to my cycle however it was on the red pill section. My period ended after 3 days but i still continued with the pills and I have been taking them for a week now.
I was wondering when it would be possible to start having unprotected sex with my boyfriend. I received my period normally after 28 days so I have ruled out all possiblities of pregnancy.
Thank you