Is Smoking Marijuana Safe While On Lamictal?

I'm a nineteen year old girl, taking lamictal for bipolar disorder, and I smoke marijuana every now and then. Someone told me that smoking weed on lamictal will effect me negatively. I have felt no different on my medication when smoking weed than I do when I am not. I don't smoke that often, but it has raised some concern to those around me. I think the mix effects people differently, and that it's different with every case. I don't feel that smoking weed has done anything different or canceled out my meds in any way, but I want to know in order to ease those around me. Can I smoke weed and continue taking my medication?