Getting pregnant immediately after a Chemical?!

Can you get pregnant right after the bleeding/period after a chemical? I’m currently waiting for the bleeding to start as my hcg levels were dropping at 5weeks my dr took me off my progesterone since he said it wasn’t a viable pregnancy. He said we could take the letrozole a few days after I start bleeding & try again immediately. Has anyone ever done this?! What do you ladies think? It’s my 3rd miscarriage this year, we had one at 9 1/2 weeks, then waited two cycles had an early loss at 6 weeks, waiting 4 months & now this very early “chemical” my hcg was 20 12dpo then 85 a week later & then dropped to 70 after another week.