Feeling discouraged

I am 28yo and my husband and I have been ttc unsuccessfully for 2 years. I have tried tracking and because my period is so irregular there is no pattern that i can find. I went to the doc, and they say that there is nothing wrong with me. I have always wanted to be a mother and I come from a big family with 5 siblings. I guess I never thought that when it came time for me to have a baby that I would have trouble. I'm just feeling discouraged, but I'm not going to give up.