Long question short: a condom AND the pill (taken perfectly)- how effective is it?

I started taking birth control in August of 18, and have never taken it late or missed. Had sex about a month later and also used a condom which worked perfect, but had constant anxiety about pregnancy or some freak “accident”. So basically, I’m too scared to do it again, and I wish I wasn’t. I’m able to understand that the only way to really prevent accidents is not to avoid everything all together. I’m just curious now as to how effective it would be if I kept doubling up? I read somewhere it was like less than a 1% chance, but still nervous. Anyone?