1 Yr TTC

I have 3 kids with my first marriage. Youngest child is 11 yrs old. I came out pregnant 3 yrs ago but was just a sack and had to get a DNC done. We put a stop to it and have been trying now for about a year. My periods are normal but at times late by a few days ever since ttc not sure why. I use ovulation kits and ovulate each month between day 10 and 15 but still nothing. Can I get any other suggestions, ideas or advise on what else to do?