Problems with Clomiphene

Can anyone help? We have been trying for baby number two for a while and I am now on Clomiphene (Clomid). I have had three cycles with no success but each time I have felt sure I conceived as I felt nauseous within a couple of days of O and stayed feeling sick up until 10 days after O (about the time of implantation) when I stopped feeling sick and started spotting. I have read that Clomiphene can cause problems with implantation. My doctor wants me to keep taking Clomiphene but now I'm worried it's having an adverse effect. with my first child I felt ill a couple of days after conception too so I know what it feels like and am pretty sure I'm conceiving each time. would appreciate hearing from anyone with similar experience or advice.