I used a trash bag for a condom and finished in my GF. Could she be pregnant?

My GF wanted to have sex but we didnt have a condom, so she found a garbage bag wrapped it around my penis & tied it with a rubberband. I finished inside her. It was the same day she started her period also. Could she be pregnant?
Update: She had her period july 4th. We had sex later in the afternoon.
11 answers 11