TTC for 5 years with no luck

My husband and I have been TTC our second for about 5 years. The last two and half years we have been going to fertility doctors and we have both been tested and told there is nothing wrong with either of us and that they don't know why I'm not getting pregnant. I've seen 3 different doctors and been told 3 different things about PCOS. one doctor says I have it, one says I dont and the other said I could have it. I am beyond frustrated. Especially since it was so easy to conceive our first. I guess I am just wondering what else we could try to help possibly conceive.