Not ‘feeling’ pregnant

Hi ladies, first time posting here. I was wondering if anyone has ended up being pregnant without actually feeling pregnant or even thinking you’re pregnant. I have a 13 month old son and my cycles have still not become regular with only 4 periods since he was born averaging 6 week cycles. My last period was almost 9 weeks ago (Jan 17) but as of last week (March 12) I was still getting a negative test. I don’t feel pregnant but still not getting a period..? When is it time to call my doctor?

TIA