We took over a year to conceive Ash, we went to our GP and she sent me for blood tests on certain day of my cycle to make sure I was O and Df sent for a sperm analysis. After the results came back (Df had low sperm count) we were then referred to fertility specialist who did a more indepth test to see exactly what was causing the low sperm count so to see how to fix it. All worked out well in the end.
Good luck.