Hard to conceive 2nd time

We have been trying to conceive for about a year now. I love him dearly and although i have a 5 yr old daughter from a previous relationship, he would like to have kids of his own, as he has none and is dying to be a dad. Getting pregnant for the first time for me was a breeze. I was taking BC but had stopped because of the headaches i had received from it (Probably why i got pregnant so easily). I have no clue as to why it's harder for me to get pregnant the second time. He Had gotten his sperm tested and yes they are marching lol. Next the doctors did some blood work and had confirmed that a certain hormone (forgotten which one) was a bit low. They recommended that i get an ovulation prediction kit. Its been a couple months since I've tried it and So far, I've had no luck in a positive result. All this is so discouraging like i wasn't made to have any more kids. ?? Anyone else experiencing this??