Depo shot vs pills

Okay so I'm planning to visit the doctors soon, to see what is best for me, everytime me and my boyfriend have sex I'm always so paranoid I'll end up pregnant even with a condom on. I'm trying to find a better source of protect where we won't have to use a condom and it'll still be extremely effective, which would be better? The pills or the shot? And I'm trying to get these without my mom figuring out I'm having access to these, I'm 18 and she will be taking me but it's just weird for her to know I'm sexually active