How long??

So we are almost at the end of month 2 of TTC, my period is not due till Sunday/Monday but I decided to test today using first response early response test and it was negative 😢 I am really beginning to loose faith. With my other children (not planned) I fell pregnant whilst on contraception. Have been completely off contraception now since mid-October and nothing. I don't smoke/drink/do drugs. I walk everywhere (don't drive or use public transport as don't need to). Are we doing something wrong? My fiance is currently taking alot of medication could this be causing fertility problems? (I am UK based)

Thanks

Hayley