Advice please, early pregnancy & progesterone

I’m pretty certain I’m pregnant again after two losses last year. However my hcg is so low I’m getting only faint lines on my hpts, I haven’t missed any period yet. My fear is that if I need to supplement with progesterone I should start now. Last pregnancy they didn’t do bloodwork until I was 7 weeks and found my progesterone was 8.5. Do you think it’s okay to wait a week to confirm the pregnancy & get bloodwork etc? (My high risk specialist said as soon as I got a positive hpt they’d do tests on my progesterone to see if I need to supplement)