Uy mama, ang injectable ay hindi agad mawawala sa system mo, usually it takes a few months pa para maging fertile ulit, kaya may buffer ka pa But honestly, since you're worried and sexually active, it's really best to see your OB asap para ma-clarify kung ano exactly ang timeline for your body, and they can also discuss other options if you're not ready pa for another baby, they won't judge, promise! A few of us mum friends went through the same worry after stopping FP, at napakagaan ng loob when the doc explained everything properly.