Trying after miscarriage

My boyfriend and I are about to start trying again in a couple weeks and I’m scared. Back in March I got pregnant with our first, but I had a miscarriage at the end of May. I feel ready to try again, as does he, but I’m scared my being overweight will cause another miscarriage. The doctors all told me that there was nothing I did to cause the first miscarriage, and that it was a “sometimes it just happens” case. I guess I just want some reassurance from other women who are overweight and have had successful, healthy pregnancies.