7months of ttc

My husbandand I have been trying to conceive for 7months now and i just found out I'm not pregnant again. So now we'll be onto 8months... I feel like such a disappointment and I'm worried I won't beable to give my 8year old son a sibling. He'sasked for years for a brother or sister and I've was sick and not in a place to go through a pregnancy without being highly stressed and my pregnancy with my son it was extremely difficult because I had HG... we didn't get around to giving him a sibling and now that I feel like I can, it's not happening. The first time we tried to get pregnant we were successful with my son... just now this time, over and over again. I've been taking prenatals, coq10, choline for 2 years to hopefully support of a healthy baby.