I agree with BluCrystal. The best way to not get pregnant is just not to do it. I know people who've gotten pregnant while on BC and using condoms, and both. Although their effectiveness rates are high, you can't always trust them. It's great that you are planning this and using protection, I'm pretty sure you will be fine. But the only way to be 100% that you won't get pregnant is just not to do it. Good luck!
To be honest, the only POSITIVE way to not become pregnant is to not have sex. Condoms can break, pills can decide not to work, etc. I'm not trying to scare you, just tell you the truth. It is also true that the precautions you are taking DRASTICALLY reduce the chances of getting pregnant to almost zero. I hope this helps. Blessings - Blu