How long after stopping birth control can you get pregnant

I am 24 I am married I have had two kids I had a implant in for 4 months I had horrible bleeding so I got it tooken Out was on a birth control pill for a month now we are trying to conceive after I stopped the pill.. how long will it take to concieve? I have been feeling nauseated headaches my boobs feel like someone punched them I keep getting negative pregnancy tests from the 99 cent store.. I have never tooken birth control before so I have nothing to go by..