How long after depo injection did you ladies get pregnant?

Hi ladies 
Sorry I'm new to this but I had one shot of depo last year (October 2014) and was due for my next one in dec 2014 but never had it as myself and my partner wanted another baby. I didn't have a period while on depo and since have only spotting for 2days for the last 2 months. 
I already have a three year old who I got pregnant with after 2 months of trying. 
I'm getting really depressed as we've been trying for months.