Vitamins to help get pregnant!?!

This morning I woke up To my period and I was for sure that I could have been pregnant, Once again! It'll be a year next month, of trying. 😭 trying to stay positive. I've seen a doctor and they said it was unexplainable infertility. They had no answer for me. They prescribed me clomid but with my high percentage of twins or multiples, it's scary to us. So we decided to keep trying and let it happen when time is right.. I'm 21, he's 26. We've already had children and those were easy to conceive. The only thing different is his medicine. My husband is on antidepressant medicine, but the doctor said it doesn't seem to be bothering my husband.

My question is, is there any vitmins or over the counter things, we can take to help our chances?