Professional help ttc?

Kaylee • TTC #1 with my fiancé. We recently accepted an offer on a house and I can`t wait to start our family. I`m 22.
How long do you wait before going to the doctor to make sure nothing is wrong? We are going on our fifth month TTC. Feeling frustrated and down. This started out fun and has turned into an obsession. When do you go to the doctor? I'm starting to get worried because fertility problems run in his mothers side of the family.