35 and ready to try again after miscarriage

My husband and I both have children from previous relationships, but we'd like to have one together. About a month after we got married we found out I was pregnant. Unfortunately, the pregnancy ended with a miscarriage. This was extremely difficult for us. I became extremely depressed and gained 80 lbs over the course of a year and a half. I've lost almost 30 lbs in the last 6 months, but am still obese by medical standards. To complicate things more I am 35 and will be 36 in a few months so time is a factor. Since the miscarriage we have not used birth control, but we also have not been tracking ovulation/cycles. I'm interested in recommendations on how to proceed. Should we just try tracking cycles and ovulation or should we try to see a specialist? I'm still working on losing the weight, which is probably the biggest factor, but I'm concerned that every month I'm getting older and fertility is declining.