Feeling frustrated...

My husband & I started trying to conceive 3-4 months ago. I am very regular & know when I ovulate. We haven't had any luck yet. I know we are doing the bd when I'm ovulating but don't know what the problem is. I've been off a medication bc my doctor doesn't want me on it when we conceive thru the 1st or 2nd trimester. I shouldn't be off it long term, but I'm not getting pregnant and don't know what to do. I feel so frustrated & hopeless sometimes. Almost all of my friends conceived 1st try...I was so worried about not being ready to have a baby and now that I'm 30 and finally ready, nothing is happening...I was told a lot of fertility specialist won't see someone who is 30 who hasn't been trying for a year. I just don't know what to do or when to take the next step...