Pregnancy symptoms but test is negative

I have officially missed my period and have had a lot of pregnancy symptoms over the last week. Light headed, headaches, exhaustion, nauseous, eating more than normal. My pregnancy tests are negative but sense I work in a OB/GYN office I had a ultrasound tech scan me. She said it looked like endometrial thickness. But was unable to see my ovaries for a corpus luteum due to gas stuck in my belly. (I have IBS so that’s normal for me) The doctor I see in my office is out till Tuesday so I can’t get bloodwork till then.

I’d be just over 5 weeks if I am pregnant. Has anyone else experienced this before?!? If so did it turn out that you were pregnant and the tests just didn’t show it yet?!?