Birth control options

While I can’t necessarily say I want to do any birth control, I can’t afford another child until this current baby is at least 3 (both dad and I work full time; without an option to really go down to one income and daycare is pretty pricy) I don’t trust the natural routes of birth control because I am super forgetful and there’s a lack of faith that I’ll do it correctly. My options are really an IUD or the pill I hated the pill as it made me gain soo much weight. No matter what I did, I couldn’t lose it; it’s as if I was retaining water. I’ve never had an IUD but don’t know much about them nor have met someone that has used it or uses it. Any tips?