post partum and birth control?

I have been really worried about this. I was on depo before we tried to conceive and it took two and a half years of being off of it to finally get my period again. And then another six months before getting pregnant. I also learned that my body is VERY sensitive to medication. All of the estrogen based birth controls are bad for breast feeding and my body just does awfully with progesterone birth control with depo being straight progesterone obviously. We do plan on waiting the entire six weeks to have sex for safety but I know it's still possible to get pregnant while breast feeding but still considered unhealthy to right away. Beside it's my husband and my first child and we want to spend a year or so with her. I would time my ovulation but don't you either not get or get sporadic periods while breast feeding? And the IUD scares the crap out of me. Am I just doomed to gamble my chances every time? I feel a bit helpless