I don't think charting alone is reliable if you want to avoid pregnancy, especially if data is not collected properly. Why not use condoms?

I want to use FAM but wondering if it will really work for me. I am recovering from surgery from a ruptured ectopic pregnancy and am down to one fallopian tube (which in theory should make TTC harder). I would like to delay TTC for a while as I have a one year old and need to recover a bit before another one but don't want to go on hormonal bc. With that being said-- I NEVER have a regular sleep pattern, am up during the night, wake at different times, etc-- will I really be able to chart successfully? What are the chances of us being able to delay a pregnancy for 6 or 8 months using w/d, charting, opk, etc?