If your birth control is a lower doasge is it a bigger chance of me getting pregnant?

im 16, my doctor has me on a really low dose of birthcontrol, if its a lower does is it easier for me to get pregnant? yesterday, i did take my pill, and me any my boyfriend still used condoms, but it popped, he did ***, and he said he felt it pop so he took it our asap. soo? can i still be pregnant? what about the lower dose?