6 weeks but conceived beginning of December?

This is really confusing me, even though it isn’t my first child. My last period was nov 16th to start. I didn’t have sex until the first of December a quite a few times after that. My first appointment was cancelled so I asked a doctor over the phone and she says I am 6 weeks conceived in the very beginning of December. This is so confusing. My cycle isn’t 28 days like normal. More around 34-36. Am I really 6 weeks. And did I really conceive this month?