Need your advice

We've been TTC for almost 10 months now. My expected period is 6 days from now, if it comes, should I go to the doctor? I am 34 and my husband is 38. We already have a 2.5 year old. Should I wait the full year? And who do I go to if I should see a doctor? My regular doctor? Do a sperm test? It's so disappointing each month. I'm beginning to think we were meant to have an only child.