When to go to the doctor?

My husband and I have been trying for 5 cycles now for our first baby. I have been using opks so I know when I'm ovulating and we try to have sex at least every other day through out the month.

When should I/we go to the doctor if we don't get pregnant? Also do you go to your regular doctor or a specialist?

I'm not looking to

I had a normal physical with my regular doctor in November with pap and all and everything was normal. I also have very regular cycles and my period comes right on time each month.

Just looking for a little advice. Thanks!