I'd just get some day 3 bloodwork done.
How long have you been trying for # 2 and how long since you delivered #1?
Are you charting or using OPKs?
OB's don't really do fertility stuff. If you've been trying for a long time, you would probably be better served by going to a fertility expert. Since you already have one child (if it was recent) then your tubes probably aren't blocked, and you most likely don't have male factor. RE's will have you go through a ton of bloodwork and testing before they will do anything for you.
Your OB might give you clomid, but IMO, it's not necessary if you are ovulating.