I lied to my guy. Am I out of line?

The other morning (day 1 of my period) we were messing around and he was out of condoms. His penis was literally inside of me for 3 minutes at the most, he didn’t climax. I’m on birth control (have been on the same one for 6 months now) and he took me to Walmart to get Plan B the next morning, but the pharmacy wasn’t open and we had to go to work... so he told me he’d bring me some if I didn’t want to get it after work. I feel kind of bad because I told him I took the plan b. But I’m also very in tune with my body and have never gotten pregnant from unprotected sex while on my birth control. Plus I was on my period, and I’m not spending $40+ on something I don’t need. Should I tell him the truth? because I’m feeling kinda bad about it.