Natural Birth Control opinions

Hey ladies, I recently have been doing some research on natural birth control and I’m trying to figure out how affective it can be. I know nothing is 100% affective but I’m trying to weigh my options out since me and my husband have 2 little girls and we want more kids but I feel like ever since I had our children my body is not working with birth control anymore. I tried trying another brand and other options but I feel like every kind messes with my hormones and makes me gain weight like crazy and I’m always moody. I am trying to get some opinions on natural birth control. Going off the pill and taking my basal temperature in the morning and tracking my ovulation. Has anyone else done this and it be affective? Can I have your opinions and pros and cons?