HELP ???

Hi everyone I'm 18 and currently TTC. Me and my partner have been together for 3 years and last year I fell pregnant we were over the moon! But after going to my 12 week scan beginning of January 2015 we found out there was a problem with our baby and there was nothing they could do. Early February we sadly had to say goodbye to our little boy :(. We are trying again but nothing is happening! Does anyone know how long it could take to concieve again?