I think this is all going to sound pretty standard, but here goes:
If your cycles are regular then taking a pregnancy strip test a couple days after you're due should give you an accurate answer. A blood test from your obgyn I think is even more accurate. I wouldn't rely only on physical/emotional symptoms. They can be misleading.
If the test says that you're not pregnant you may consider contacting a fertility specialist, although at your age they may prefer that you continue trying for a few months longer. There are many options that a fertility specialist can discuss with you. He/she will tailor a treatment plan designed especially for you based on your age, the results of a few tests, etc.