Low sperm concentration

J
Hello. I hope I'm posting this is the right forum. 
My husband and I have been TTC for the past year and a half. I've gotten an hsg done and it was perfect, I've tracked my ovulation and I'm ovulating perfectly and on time every month, now my husband had gotten his Sperm analysis results today and I'm devastated. They said he has low sperm concentration. I'm not too sure what that means, other then the fact that he hasn't got a lot of sperm in his semen. Also they said he has to go to a urologist for more testing. I don't know what other testing they could do but why can't they just put him on clomid? I'm so depressed, I don't even know what to say to my husband. We have a child together already. It only took three months to conceive him, idk what happened!! I'm so confused. Anyone have any advice or stories you could share with me?? It'd be greatly appreciated ... Thank you