Late period, negative tests

I’m 15 DPO, been having waves of nausea (I never get nauseous which is what started my POAS addiction this cycle) lower back pain, AF has not arrived, yet all my tests are showing negative 😑

I usually have a 32 day cycle, AF was supposed to be here Monday… I had one test that looked faint positive (but it was so faint I couldn’t tell if it was an indent) but all other tests look negative since.

Messaged my Dr office, they told me to take another test & send them a pic. They said it looked negative. When I asked if I should schedule an appointment to have blood work done just to make sure they told me to continue to monitor. So how long do I “monitor” before I reach out to them again to try to get an appointment set to figure out what’s going on??

We want more kids, but I also have a surgery coming up where my Dr told us we need to wait to try for more until after my procedure.

So I guess I’m just trying to figure out if anyone else has gotten positive tests back after 15DPO & when should I insist on a Dr appt for blood work?